Hello, currently I have a VestaCP install, it's able to send and receive emails from the webmail (roundcube) however when I try to send any email from a Desktop client (Mozilla Thunderbird or MS Outlook) the mail gets rejected.
I always get the following message: An error occurred while sending mail. The mail server responded: Helo name contains a ip address (HELO was [192.168.1.50]) and not is valid. Please verify that your email address is correct in your mail preferences and try again.
I have checked the exim logs and they show the same error, the only difference is that they show 2 IP’s (WAN IP and local IP, the computer is behind a router). This problem happens every time a user try’s to send an email and he/she is behind a router. I have tested the 2 local ISP’s with different router’s and it’s the same issue.
The only addition I made to my install, was installing CSF. I have tested disabling CSF, rebooting the server and the problem persists.
Do you have any suggestions or possible fix?