Outlook emails blocked due to RBLs

[albatroz]

I have this issue with an email account in my Plesk Linux VPS.

When I send an email using Outlook it almost never arrives to its destination.

Having checked the issue, it seems to be a RBLs issue. My customer's dynamic IP is blacklisted.
However I don´t understand why I don't have this problem when I send an email from the same
computer using Webmail.

 

[breun]

If you have enabled an RBL that blacklists dynamic IP addresses, then yes, your mail server will block an email sent from a dynamic address. Check a blacklist's policy before adding it to your list, because you might be locking you or your customers out if you are not careful.

The same message sent through webmail will not be blocked because then the 'mail client' (the webmail interface) and the SMTP server are on the same machine and the message technically comes from localhost.