Outlook Cannot Send Messages Suddenly

[PostAlmostAnything]

This bug was noticed yesterday. I have a variety of domains which use a specific cPanel server for email. They always worked fine until yesterday when Outlook stopped being able to connect for the purpose of sending any messages. I still receive them all just fine and can send if I login to webmail via cPanel, but for whatever reason it is not possible to send from desktop.

This must be a problem on your end since I changed nothing on mine.

I have done all I can think of on my end. All I could think of was to reboot the server.

Why would I suddenly be able to still receive but not send any message?

DO NOT tell me to reset passwords since that is NOT the problem.

 

[cPRex]

Hey there! I'm sorry to hear about the issue with Outlook. Do you have root access to the server? Many providers are limiting access to port 25 on their networks, so it's possible there was a network change causing this problem.

A quick way to test this would be to perform a "telnet" test from one of the affected computers to the server to see if that port is open. First, you'll want to make sure telnet is enabled on your machine by following the details here:

https://social.technet.microsoft.com/wiki/contents/articles/38433.windows-10-enabling-telnet-client.aspx

After that, you can open a command prompt and type the following command:

telnet domain.com 25

where "domain.com" is one of your affected domains.

Can you try that and see if that connection works?

 

[PostAlmostAnything]

I have root access, but I don't use port 25 because Century Link won't allow outbound connections on that port.

 

[cPRex]

Can you try the test with the current port you're using? That may be 26 or some other alternate port.

It's also important to note that we don't provide your hosting - we do create the cPanel software that your hosting provider users, but we have no control over your personal server or hosting environment.

 

[sparek-3]

What specific settings are you using in your Outlook?

If you're connecting securely either through tls_on_connect or TLS upgrade - has the secure certificate for the used hostname expired?

Do you have cPanel automatic updates enabled? No real clue if cPanel recently pushed out any updates, the cPanel folks here would have a better idea of that.

Do you have automatic OS updates enabled? Perhaps an update to OpenSSL or Dovecot happened that you were unaware of.

 

[PostAlmostAnything]

I use port

Hey there! I'm sorry to hear about the issue with Outlook. Do you have root access to the server? Many providers are limiting access to port 25 on their networks, so it's possible there was a network change causing this problem.

A quick way to test this would be to perform a "telnet" test from one of the affected computers to the server to see if that port is open. First, you'll want to make sure telnet is enabled on your machine by following the details here:

https://social.technet.microsoft.com/wiki/contents/articles/38433.windows-10-enabling-telnet-client.aspx

After that, you can open a command prompt and type the following command:

telnet domain.com 25

where "domain.com" is one of your affected domains.

Can you try that and see if that connection works?

When trying to run telnet on domain.com 465 I get an error saying "telnet is not recognized as an internal or external command"

 

[cPRex]

That sounds like you need to enable the software using the first guide I linked.

 

[PostAlmostAnything]

What specific settings are you using in your Outlook?

If you're connecting securely either through tls_on_connect or TLS upgrade - has the secure certificate for the used hostname expired?

Do you have cPanel automatic updates enabled? No real clue if cPanel recently pushed out any updates, the cPanel folks here would have a better idea of that.

Do you have automatic OS updates enabled? Perhaps an update to OpenSSL or Dovecot happened that you were unaware of.

I am using every specific Outlook setting that I've always used. If any certificates are expired it would be due to AutoSSL screwing up again, but it doesn't appear that way. I don't know if I have cPanel auto-updates enabled or not. Again, don't know about automatic OS updates either. I assume cPanel must be configured out of the box to do auto-updates because that is how software is supposed to be setup by default.

 

[PostAlmostAnything]

Can you try the test with the current port you're using? That may be 26 or some other alternate port.

It's also important to note that we don't provide your hosting - we do create the cPanel software that your hosting provider users, but we have no control over your personal server or hosting environment.

I host on an unmanaged VPS with root access which I have not changed in awhile. My hosting company is hands off, so that means they probably changed nothing at all.

What software did you link to? My SMTP port is port 465

 

[PostAlmostAnything]

Turns out telnet has to be enabled in Windows Control Panel and is not enabled by default. Now I get the following for telnet domain.com 465 without quotes "_"

 

[sparek-3]

If your Outlook is configured to use port 465 then you are likely using tls_on_connect - so the telnet test to port 465 probably isn't going to tell you very much.

Are you sure Exim is running?

Have you restarted Exim?

/scripts/restartsrv_exim

Or there's probably a link in your WHM to do this too.

 

[PostAlmostAnything]

If your Outlook is configured to use port 465 then you are likely using tls_on_connect - so the telnet test to port 465 probably isn't going to tell you very much.

Are you sure Exim is running?

Have you restarted Exim?

/scripts/restartsrv_exim

Or there's probably a link in your WHM to do this too.

What is Exim? I've seen references to it before, but have never had a reason to ask what it is before

 

[PostAlmostAnything]

Also, please don't give me console commands as if I know what part of a linux machine they might refer to. I would have to login via WHM and then use the terminal just to input them and I hate doing that. Could you please describe how to do the same things in WHM or cPanel without the terminal from now on?

 

[PostAlmostAnything]

Accidental comment, but couldn't find option to delete, just to edit.

 

[sparek-3]

Probably not the best thing to run on an unmanaged service if these commands and items are foreign to you.

That may sound condescending, and I don't mean for it to, but there's some truth in that.

If you're going to use an unmanaged or self-managed system you probably need to know how to diagnose issues like this.

 

[PostAlmostAnything]

What is Exim? I've seen references to it before, but have never had a reason to ask what it is before

Yes, it does SSL to connect. The exact Outlook option used is called SSL/TLS, but that should not be a problem because this server has been running email exactly the same way for over a year until yesterday.

 

[PostAlmostAnything]

Probably not the best thing to run on an unmanaged service if these commands and items are foreign to you.

That may sound condescending, and I don't mean for it to, but there's some truth in that.

If you're going to use an unmanaged or self-managed system you probably need to know how to diagnose issues like this.

I thought if I ran an unmanaged system all I should need is software like cPanel to manage email for me. Its not that I cannot use the terminal, but I use it rarely due to it not being necessary unless cPanel screws up somehow.

 

[PostAlmostAnything]

Isn't there an option (or at least there should be) to restart Exim WITHOUT the terminal? I seem to recall seeing just the thing in WHM last night (see below):

ERROR! Cannot find option to add image to comment.

Why give me a command line directive instead of telling me to open WHM, find the part featured above, and use it?

 

[sparek-3]

Well... cPanel is just a tool.

Now, you can argue that cPanel has marketed itself as some magic tool that automatically does everything you ever need - I might join you in that argument. But in the end it's just a tool.

With ANYTHING that is on the Internet there is no such thing as a "install this and leave it and never have to worry about it ever again!" Has cPanel and other control panels peddled themselves as such? Maybe. But it's a marketing scheme - it doesn't make it true.

 

[cPRex]

cPanel makes managing many things on the server easier, but it doesn't replace server management troubleshooting skills when things go wrong.

You can restart the Exim mailserver from WHM >> Restart Services.