problem sending emails

[ffuchs]

hi,

we are using a cpanel-installation (version 88.0.14) from a hetzner.com reseller. we have only access to the cpanel area and not to the whm area.

on this cpanel-installation is a wordpress-website. we had no problem for the last year to send emails with the plugin Easy WP SMTP, the email-address is hosted on office365.

since last week we get the following error message:

SMTP ERROR: Failed to connect to server: Network is unreachable (101)

I tried this email-account on a different webhost (not cpanel, a normal internet-provider) with the same setup: wordpress + smtp-plugin + office365 mail-account -> no problems.


so I tried a simple imap/smtp mail-account from all-inkl, here I get this error message:

SMTP ERROR: Failed to connect to server: Connection refused (111)

we contacted the cpanel-reseller who has access to the whm-area and he said, there are no special firewall rules active or changed in the last week.

my next idea was to use the mailserver from cpanel, so I added the ip-address of the cpanel-installation in the spf-entry of the domain (but no mx-record) and created the same email-address on the cpanel as we use on office365.

with this setup I get the following error-message (domaininformation "anonymized"):

CLIENT -> SERVER: EHLO www.acmecorp.com
CLIENT -> SERVER: STARTTLS
CLIENT -> SERVER: EHLO www.acmecorp.com
CLIENT -> SERVER: AUTH LOGIN
CLIENT -> SERVER: [credentials hidden]CLIENT -> SERVER: [credentials hidden]CLIENT -> SERVER: MAIL FROM:<[email protected]>
CLIENT -> SERVER: RCPT TO:<[email protected]>
CLIENT -> SERVER: DATA
SMTP ERROR: DATA command failed: 530 Relaying not allowed

so now I'm a little clueless, what I should do next.

I think to send locally should be the easiest solution to solve, so I would like to ask, if I have to configure more in cpanel to allow relaying, I simply added the mail-account but couldn't found further settings to configure.

many thanks for your help,


ferdinand

 

[keat63]

I'm guessing the reason behind you not being able to send locally could be related to your DNS mail entries pointing to Office365, although this is only a guess.
As for connecting to Office365, have you considered that your IP might be blacklisted.

Maybe take a look at MXToolbox.com and have a play around with the testing tools.
Also check your domain name and IP address using thier RBL tool.

Email Blacklist Check - IP Blacklist Check - See if your server is blacklisted

mxtoolbox.com

 

[ffuchs]

hi keat,

thanks for your tips, the mailserver has no blacklist-entries at mxtoolbox.com.

regarding this error message:

SMTP ERROR: DATA command failed: 530 Relaying not allowed

where do I configure relaying? please notice, that I only have access to cpanel but not whm.

many thanks,


ferdinand

 

[cPanelLauren]

You absolutely would not want to configure relaying, this is all around a bad idea. The error message you're receiving indicates an IP block:

SMTP ERROR: Failed to connect to server: Connection refused (111)

While the provider may not have explicitly added any firewall rules it's possible it could have been automatic or the port you're attempting to connect to is closed. Either way, the issue here is ultimately that your server is unable to connect to the remote server to send mail and the provider for that remote server should be able to identify the issue.

 

[ffuchs]

dear lauren,

many thanks for your input. I don't think the problem is the mailserver, the mailaccount is on office365 and if I use microsofts tool to unblock an ip-address (Delist IP - Delist IP), the result was, that the ip-address of the cpanel-installation isn't on microsofts blacklist (and the blacklist-check from mxtoolbox.com also doesn't show any blocking blacklists).

I also tried

- a different mailaccount from a completely different office365 tenant - same problem
SMTP ERROR: Failed to connect to server: Network is unreachable (101)

- I tried mailaccount from a normal local ISP, also doesn't work, but strangely with a different error message:
SMTP ERROR: Failed to connect to server: Connection refused (111)

I think the problem is the cpanel-firewall, but I don't have access the the whm-settings and our reseller says, he checked the firewall and for him the firewall isn't the problem. for several reasons we can't shift to a different reseller at the moment, so we have to deal with the situation.

is there any way to proof my assumption, that the cpanel-firewall is the problem, so I can put pressure on our reseller?

therefore my alternative would be to use the cpanel-mailserver, but here are problems too as I wrote.

many thanks for your help in advance,

cheers,


ferdinand

 

[cPanelLauren]

More than likely it's not cPanel's firewall that does this it's whatever they have installed on the server. From a putty or terminal session outside of the server you could potentially run something like the following for the port you're attempting to send mail on:

nmap -Pn hostname.yourserver.tld -p 25