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How to Fix “503 valid RCPT command must precede DATA” Error

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Help meFor those that are tearing their hair out when getting the “503 valid RCPT command must precede DATA” error (we’ll refer to it as simply the “503 error” going forwards) when trying to send email, here are some common solutions that will hopefully get you back up and running. If these don’t work, or you need more detail on any of these steps, please read the rest of this article, and its comments, for some more in-depth solutions.

Possible Solutions for 503 Error

  • Apostrophes – remove any apostrophes (single quotes) or other non-alphabetic characters from your email account name(s).
  • VPN – if your system is trying to connect via a VPN network while you’re sending email, you may get this error. Try disconnecting the VPN before sending/ receiving mail.
  • Full mailbox – make sure the mailbox of the affected account is not full or has met/ exceeded its quota. You can uncheck the following option to make sure a copy of all your emails is not being left on the server (note that since the email will be downloaded to your PC after this setting change, you won’t be able to access your emails from another location if you do this). In Outlook, browse to Tools > Account Setting > More Settings > Advanced > Uncheck “leave a copy of this message on the server.”
  • SMTP port – use port 26 (instead of the default 25) for outgoing mail.
  • Server authentication – setup your outgoing mail to use outgoing server authentication (sends mail by logging in with your email address and password). In Outlook, browse to Tools > Account Settings > More Settings > Advanced and change the outgoing server to ‘Auto.’ Next, browse back to More settings > Outgoing server and check the “My outgoing server uses the same authentication as my incoming server” box. If you select to have Outlook “remember your password” you won’t have to type it in every time you send an email.
  • Sender matching – make sure you’re sending from the same email address that the recipient sees your email coming in as (ie. don’t make the “from” field differ from the email address used in your outgoing mail settings).
  • Outlook PST files – sometimes the 503 error will occur if you have a corrupt Outlook PST (mail archive) file. Try repairing the file.

If none of these approaches work, or you need more detail on a particular step, please read the rest of this article for some additional suggestions.

503 Valid RCPT Command Must Precede DATA

We recently got this error when trying to send an email in Outlook. The culprit? Apparently, this occurs when a server is expecting to receive mail before sending. This is usually results from server authentication priorities (for example, you attempt to send mail before your “spam filter” has finished its receiving process.)

Solutions to Resolve the 503 RCPT Error

  • Pop before SMTP — Run a check for new messages (F9 key in Outlook) before sending your message and restart and rerun your spam filter application. Your IP address is entered in a relay hosts file, allowing email to be sent from your address for up to half an hour.
  • If the problem still persists check “my server requires authentication” to authenticate automatically. With this setting, you can bypass the check above and send mail without having to “pop” your mailbox first. You can also try changing the outgoing port from 25 to 26, since some ISP’s block this port.
  • Several of our readers have pointed out that it may help to remove apostrophes from your email account names (and ask senders to remove them if you’re having trouble receiving emails from them).
  • If you’re on a VPN, try disconnecting from the VPN prior to using your mail program.
  • Your mailbox may be full – try clearing out messages or asking your mail service provider to increase your mailbox limits.
  • If you are using multiple mailboxes, make sure these fixes/settings are applied to each one of them, especially the “default” one.
  • Finally, if using a mail screening utility such as Mail Washer, you may want to disable the “automatically check at intervals” setting and check mail manually. If the system checks mail while you are sending you may get this error.

Still Having Trouble?

If none of the above work we recommend contacting your hosting provider. Your mail services account needs to be set up properly (associated with the right username, etc.). We encountered this exact problem when switching hosts once – the mail server configuration got goofed up, and none of the above solutions worked. In the interim (until settings are fixed by your hosting provider) you can adjust your outgoing mail server to reflect that which your ISP uses, which should let you send mail again through your local client (Outlook, but not from the server (Webmail), until the problem is fixed.

As mentioned previously, to keep your mail system running smoothly, and to help you get rid of various email related errors, including the 503 valid RCPT error, we recommend installing a solid anti-spam solution. Anti-spam software is affordable, but your email and privacy are priceless. Don’t let the spammers get the best of you. For a limited time, get a free trial of Spam Bully.

Have you had this issue before?

Alex bring a series of in-depth articles on search marketing and content management systems as well as troubleshooting tips to We Rock Your Web's collection. He is an avid tennis player, nature enthusiast, and hiker, and enjoys spending time with his wife, friends, and dogs, Bella and Lily.

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76 Comments on "How to Fix “503 valid RCPT command must precede DATA” Error"

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Lutaaya Gad
Lutaaya Gad

it really worked for me. thank you very much i.e server authentication

Wellington
Wellington

Empty your email box, this solved my problem.

Gary
Gary

Removing non-alpha characters from my account name resolved the 503 issue. Thanks, Alex!

Andrzej Cojg
Andrzej Cojg

It is also worth noting that Outlook might have some difficulties while sending your message if your password consists of certain special symbols. In my workplace, using capital, small letters, numbers and symbols is a must for overblown security reasons. Reset your password to something less challenging and try again.

Side note: This problem could be related to your system language and coding (unicode, ansii, utf-8).

Irshad
Irshad

Open Outlook click on Tools(2007) / File(2010) > Account Settings > Highlight the email account > Change > More settings > Outgoing server > Check the box ‘My outgoing server (SMTP) requires authentication’ > Verify that the circle-box ‘Use same settings as my incoming mail server’ is selected.

Carina De Almeida
Carina De Almeida

Thanks Alex – port 26 did the trick!

Skewiff
Skewiff

I suddenly got this error message yesterday after years of doing nothing different! The server authentication (email address / password) was duly added and now it works – go figure!

Boba Fett
Boba Fett

Boom! Port setting worked like a charm! Thanks.

Hussein Aladin
Hussein Aladin

This helped a lot. Changed the server authentication to “auto” and now I am able to send outgoing mails. Thanks!!

Kimberly Alt
Admin
Kimberly Alt

Glad this solution worked for you! Thanks for letting us know about your success!

Dmitro
Dmitro

I’m trying to set up my website email through just host and getting a 503 error when receiving emails. When I use a gmail account to send to my domain address email, I receive “503 This mail server requires authentication when attempting to send to a non-local e-mail address”. I tried looking everywhere and no matter what I do I can’t receive emails. Any help would be appreciated! Thank you.

Kimberly Alt
Admin
Kimberly Alt

Is there any more information you can give us about your problem?

Andy
Andy

Great help…one of the suggestions worked! Thank you.

Kimberly Alt
Admin
Kimberly Alt

You’re welcome! Glad we could help!

h82bL8
h82bL8

No help – bunch of technical jargon.

Kimberly Alt
Admin
Kimberly Alt

Is there a question you have that we can help you with? If you’d like, you can explain your problem in detail and we may be able to explain it in another way to solve your problem.

Justin
Justin

Got it! Server auth and/or SMTP port change did the trick!

syed
syed

Hi, I have checked with authentication of SMTP and I have changed the SMTP port also from 25 to 26 then also i cant able to send or receive any emails. Please help me out from this issue.

Madhavan R
Madhavan R

Hi. As you had advised i had repaired the PST file for four hours (10 GB) and then found the same error occurring again, i deleted and re-configured the email id in the Microsoft Outlook that simply solved the error. Thought authentication – we use authentication mode for our outlook. Any ways, thanks a lot for your post and support!

Deborah
Deborah

I keep getting this message when using my 3G card – tried all the changes you suggested – still not working …

L

I just changed the port and it worked for me. Thanks!

a web rocker
a web rocker

thanks for sharing.. very helpful!

a web rocker
a web rocker

thank you friend you’ve solved my problem

Charlane
Charlane

My email had been working fine for quite some time now and today every 2nd email I send gives me the 503 error.

I tried everything, but noticed that “My outgoing server (SMTP) requires authentication” was not checked, so I checked it, but now when i click next is wants to send a test email and then i get this error:

Send test email message: None of the authentication methods supported by this client are supported by your server.

Now I just don’t know what to do. Please help!

a web rocker
a web rocker
I went through all of the above fixes and none of them worked for me. I was getting the error trying to send email from a web page using ASP/VB & ASPEmail. I actually found the fix on another site that said the following: Most probably, this error means your script is not calling any of these methods: * AddAddress * AddCC * AddBcc As a result, AspEmail gets no recipient addresses to send a message to. Check the logic of your code. If you are calling AddAddress/AddCC/AddBcc in a loop, make sure the body of the loop is entered… Read more »
Giles Tennick
Giles Tennick

After the wife managed to spill tea all over my work laptop, I had to swap over to the old desktop and my outlook settings were almost working apart from this error on sending emails. Was getting super frustrated so a huge thank you to whoever wrote this thread, I really appreciate it!!

Windwave
Windwave

Come on! Don’t blame your wife for the tea while it’s your laptop and you are probably responsible for the spill. Even though your wife spilled it, you should be ashamed of blaming her here on this forum.

vicki
vicki

Changing SMTP port – use port 26 (instead of the default 25) for outgoing mail.

& Server authentication worked for me.

Many thanks!

Kimberly Alt
Admin
Kimberly Alt

Glad to hear it worked for you Vicki! Thanks for reading and commenting.
-Kimberly

JC

Changing the port to 26 and it worked. Thank you!

Anonymous
Anonymous
The contents here are excellent. The solution to 503 problem: 1. Uncheck the ‘Tools->Account Setting->More settings->Advanced’ page’s Delivery ‘Leave a copy of…’ so that the server space is freed once you download a mail successfully. 2. No single quotes in the names of the recipients (MS never thought of that for that matter) 3. (This is what worked for me) Go to ‘Tools->Account Setting->More settings->Advanced’ and change the outgoing server to ‘Auto’ and again change ‘Tools->Account Setting->More settings->Outgoing server’ and check on the ‘My outgoing server uses the same authentication as my incoming server’ on. If you have set not… Read more »
Christiane
Christiane

My outlook gave this error message, so I followed the steps above, changed to secure authentication and so on, it got worse, so I unchecked the authentication again and now it’s working just fine.

Does that equal beating the system over the head and then it wants to work?

I don’t get it, but something helped.

thanks.

Riqt
Riqt

After testing all the above and nothing solved it. It turns out that our ISP (Telepacific) was blacklisting our domain/server and they said that a pc at our office was probably sending a lot of spam. We checked and it turns out that all the antivirus were working, active and updated, so they took us OFF the blacklist and the problem was solved.

Jeremiah
Jeremiah

This worked for me!

Server authentication – setup your outgoing mail to use outgoing server authentication (sends mail by logging in with your email address and password).

Anonymous
Anonymous

I got this message and it turned out to be related to my mailbox being full. After my limits were increased the problem resolved itself.

Anonymous
Anonymous
I have seen a few errors where people have mentioned that the only get this error when replying or forwarding and NOT when they create a brand new email. This actually is very easy to resolve and is simply an Outlook Client oversight. If you have multiple mailboxes, much like I do set-up to send and receive within your email client (I have 5 e.g. info@domain.com and info@domain.co.uk and marketing@domain.co.uk etc) then each of these mailboxes need to have the box for “my server requires authentication” ticked. Check each and every mailbox account you have setup to send and receive… Read more »
Nicky A
Nicky A

I’ve spent the last 4 hours trying to solve this problem. My outlook was working fine yesterday and today nothing. I hate computers and find it all very high tech. I had tried everything, read several online solutions and nothing was working. I have two mailbox accounts and your solution was spot on. Big sigh of relief here. Thank you!

Kimberly Alt
Admin
Kimberly Alt

Nicky I’m so glad this forum could help you! Thanks for reading and happy emailing 🙂

Anonymous
Anonymous

Thank you very much for sharing this helpful information. I think that your advice did the “trick” for me. Have a fantastic day!

Sincerely,

Ralph Flores

US – San Diego, CA

Anonymous
Anonymous

This was right on the money with the issue I was experiencing! Thanks again web rocker!

Anonymous
Anonymous

Thank you so much, your advice was spot on. I have been trying to send emails for ages. The moment I took your advice they started going through. Thanks again!

Anonymous
Anonymous

I think just make sure from your service provider that you can use port 26 for SMTP.

Thanks

Shahab

Anonymous
Anonymous

After going to Microsoft.com and spending several HOURS of my Friday night and into Saturday morning looking for the reason and fix for this problem, I finally landed here on your website and voila! The solution!! THANK YOU!!

I can now go to bed and know that my business will be functioning smoothly again when I get up in the morning.

Too bad Microsoft couldn’t have provided me with this information sooner. 🙁

I’ve bookmarked your website for future reference and plan to share it with others. 🙂

Anonymous
Anonymous

Once I had an unpleasant situation with my Outlook pst files. Luckily I found a good solution – pst repair, which took care of my Outlook errors and made my email program run better.

Anonymous
Anonymous

How did I solve it?

Check for the space allocated on server for inbox mail.

The mail box had 50mb maximum and it was full. Didn’t cross my mind until I sent an e-mail from my other mailbox on the same server.

So as a solution, verify the mailbox disk space from the server side.

Horatiu I

Anonymous
Anonymous

thank u, it works!

Anonymous
Anonymous

Thanks for the article. First suggestion I tried worked for my users. 🙂

Anonymous
Anonymous

Wow that was annoying to deal with. Thanks so much for addressing the issue – I’m hoping I won’t be seeing the 503 problem creep up again – fingers crossed!

Anonymous
Anonymous

Thanks for the info on your site! Saved me 🙂

Anonymous
Anonymous

Many thanks for the info on your website… worked a treat.

Neil

Anonymous
Anonymous

I am having the same 503 error sending email to anyone with a – in the name like XXXX@T-mobile.com. I tried to send from our company server and earthlink with the same results.

Anonymous
Anonymous

I got this error when sending email while I was VPN’ing to another network – I had forgotten to disconnect the VPN connection first.

Anonymous
Anonymous

We got the 503 error message on our email system and found that it was because the recipient had an apostrophe in their account name. As he was one of internal recipients, we have removed the apostrophe, ie (from Oneill to Neill). I spoke with Microsoft and they blamed the ISP. I talked to the ISP, and they blamed Microsoft. I need a second opinion, and I need help to solve this problem. Your help would be greatly appreciated.

Thank you

Gloria Fanucci

Mark E
Mark E

My error appears to fall into the uncommon faults. 503 valid RCPT command must precede DATA. My email was workin fine for the last 3 weeks whilst in the UK, now I am back at work in Iraq I can no longer send emails, this also happened before I went on leave so am assuming it has something to do with being abroad.

Can you please help.
Regards,
Mark

euro 2012 tips
euro 2012 tips

Finally, my outlook problem is solved. I was facing outgoing problems that are now fixed!

Phoenix in Tampa
Phoenix in Tampa

Went right down your list and of fixes and found the problem in Server Authentication by changing the setting from None to Auto. Nice work – even a non-geek like me walked right through it.

Hana
Hana

Thank you so much! I had this problem when I was upgrading to Outlook from Outlook Express (which I couldn’t stand anymore). Everything went fine except for this error message that I got when composing a new mail (strange that when I was replying to a message from my inbox, it was okay). Step 5 “Server Authentication” fixed everything. Thanks again.

Wenura
Wenura

Awesome. This totally helped me rock around the annoying 503 valid RCPT command failed error 🙂

Anonymous
Anonymous

If you need help to rectify the 503 error totally, and to rectify queries which are taking much execution time, you may have a problem with a huge mysql database. You can contact me at pankajash at gmail dot com or info at netleon dot com for assistance.

Anonymous
Anonymous

I get the same 503 error code on AOL. How would you fix it on an America Online email account?

Anonymous
Anonymous

We just implemented a new vpn service and found that we started getting these 503 errors. It took us days to figure out what was wrong until we came across your blog! Thanks.

Anonymous
Anonymous

I have started to frequently get this error, when I try to send email from outlook 2003
The following recipient(s) could not be reached:
‘xxxx@xxx.com’ on 03/08/2007 10:48
503 valid RCPT command must precede DATA
This doesn’t happen every time, but frequently. Do you know what the error means and what I can do to correct it?

alexc
alexc

Hi there,

Please take a look at our article above for some updated suggestions in helping you resolve the 503 error. You might also want to try removing apostrophe’s from your email account names.

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