Hey people...

Oh dear GOD i really need your help.

So it's come to this... none of the accounts of my WHM Control Panel can send email. They can recieve email fine! But sending... thats just a different sorry. 503 errors EVERYWHERE:

From: System Administrator
Sent: 22 January 2007 10:21
To: 'xx@xxxxx.com'
Subject: Undeliverable: test 10.21
Your message did not reach some or all of the intended recipients.
Subject: test 10.21
Sent: 22/01/2007 10:21

The following recipient(s) cannot be reached:
'xx@xxxxx.com' on 22/01/2007 10:21
503 valid RCPT command must precede DATA

Our hosting is from lucidnet.com
Our domain is firelabs.net

This isnt just from one computer... its from multiple computers in different locations. We've been having this error for about 10-14 days now... and when we first started getting the error, it was just one account on the same domain getting it. But one by one... every email account was dying.. now the whole server is kaput when it comes to sending emails.

We've tried everything in the book. We've had the same problem with 2 different reseller hosting "companies". We had the problem on the first server.. same thing - it was working then it died. So we moved to a new server... everything was happy. Then *BANG* they all started dying one by one...

Webmail will always work fine... but for our clients this isnt what they want - they want to use outlook. WE WANT them to use outlook. We've ruled out the computers (tried it on over 10 computers) , the networking hardware (we went out and bought new routers and switches) the ISP (we tried it on three different ones)...

We've carried out SO MANY tests on DNS stuff.com and anything mail related always comes back clean... what could be the problem? I really could do with your help.

I'd appreciate it if you could give me any advice... just ask questions and ill throw answers back to help narrow down the problem...

Many thanks...
Kieran.

This is not necessarily a problem with your host...

Configure your email client to authenticate before sending out mail. To do this, in your email program, check the option "my server requires authentication". The username and pass should be the same as your pop3 settings..

Alternatively, you could also check your email, and then send it. That will authenticate you as well..So press "Send/Receive", after mail has been checked (i.e. you have connected to your pop3 mailbox), then send the email..

I believe that should fix the problem :)

This is the first thing we tried. We have just tried it again and got:

From: System Administrator
Sent: 22 January 2007 12:18
To: 'xx@xxxx.com'
Subject: Undeliverable: test 12.17
Your message did not reach some or all of the intended recipients.
Subject: test 12.17
Sent: 22/01/2007 12:18

The following recipient(s) cannot be reached:
'xx@xxxx.com' on 22/01/2007 12:18
503 valid RCPT command must precede DATA

Check this: http://support.justhosting.ca/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=43

Set your email client to check emails before to send or if that doesn't fix the problem, Configure your email client to authenticate automatically by checking the "my server requires authentication" box in your email configuration. You will be able to send mail without having to "pop" your mail box first.

Check this: support.justhosting.ca/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=43

This is the response we got:

Test with port 587 came back with smtp server not responding

Test with port 465 also gave the same error.

I have tested both ports with SSL and without.

I have also tested port 26, even though it is a linux port with the same
responce

we have tried this numberous times too...

anyone else got suggestions?

Is it just you facing the problem ? or there are other people on the same server (from different locations with different ISP's) facing the similar problem.

Check if your ISP IP is not blacklisted in any of the spam blacklists implemented by your host. Ofc, this is just a suggestion - not a perfect solution though!

Hi there,

Thanks for the suggestion - we did check out our ISP etc for all the usual suspects. All came back clean.

BUT WE DO THINK WE'VE FOUND THE PROBLEM!

In WHM, we modified the DNS Zone for the domain in question.

The 503 error we was getting was a tough one - we had tried EVERYTHING in the book but EVERY computer we tried it on (about 20, all different locations, varied different ISPs) was getting the error.

So... what we did, was in the MX field, where the domain read:

example.com we changed this to mail.example.com

Then, below that where the CNAME resides for the mail field, change it from CNAME to an A record, and inserted our servers IP address.. and then we saved. After giving it a few hours to propogate, all the email accounts started working. We hope that this has solved our problem - it seems to have so far.

I hope this helps someone out there because this has been racking our brains for alonggg time. As you can see from the posts above, this wasn't a normal 503 error. It was something ... else...

Thanks for all your help!

I've experienced an identical problem to this on one of my cPanel-hosted accounts. After performing the exact same routine of tests, troubleshooting, rearranging how clients authenticate before checking and sending emails... Nothing seemed to work, I got the exact same error message first on a POP3 account checked by my phone's copy of Pocket Outlook when trying to send emails... Then stopped... And then, a week later, started to act up again.

And then my primary email address started to do it.


So, after rapid discussion with my host, it just... stopped doing it! So I guess in hindsight they must've modified my DNS records to effect the same solution (my host controls the records on that particular domain, mainly because I don't need to have personal control of them right now - I'm in charge of more than enough other things myself!). While the problem was there, it did seem somewhat intermittent - not always doing it when trying to send emails, but it was totally unpredictable. It's not happened since though, so touch wood it's all ok now I guess ;)

Supposed what I'm trying to say is that this doesn't just happen on WHM-managed domains! So beware of this mysterious problem if you're in charge of any kind of control panel-managed hosting. :)

Glad to know the problem was traced and resolved.

I've experienced an identical problem to this on one of my cPanel-hosted accounts. After performing the exact same routine of tests, troubleshooting, rearranging how clients authenticate before checking and sending emails... Nothing seemed to work, I got the exact same error message first on a POP3 account checked by my phone's copy of Pocket Outlook when trying to send emails... Then stopped... And then, a week later, started to act up again.

And then my primary email address started to do it.


OMG im SO happy that it's not just me that has had this issue... but lukily for you, your host seemed to have had some knowledge of this type of issue... where as my host had no knowledge for this type of issue. 2 weeks and 3 huge phat support tickets later... WE as in FireLabs.net had researched the answer, and made the changes ourselves.

You know what made me laugh tho? When we first changed the settings in the WHM control panel for the DNS Zones.. you know.. to the settings that was going to fix the system - we got two replies from our ticket claiming that they fixed the problem. I was really happy! ... ... only to go into my DNS Zone and find that they had changed it all back. So we had to change it back, tell them not to touch it, and wait for it to propogate again.

Thanks again for your support guys... and like i said - i really hope this helps someone else in future :agree:

Good to hear you seem to have resolved the problem but what http://dnsreport.com/ tell you now? Any problems shown?

Good to hear you seem to have resolved the problem but what http://dnsreport.com/ tell you now? Any problems shown?

Hey people. Just a quick update... yes we ran a DNS report... but all of a sudden our mailserver died and we're not too sure why. We emailed Lucid but lukily the email server was fixed relatively quickly. We ran a DNS report and everything was fine. But then we started getting 503's. We thought this was going to be another string of problems... as if we had started back from sqaure one. But the problem disappeared within a minute.

Everything is A-OK! ... ... for now.