I'm struggling now for more than 4 days / nights with following problem.
I changed my provider and now my IP is fixed, but from a dynamic IP Range.
Everybody knows what happens now. So I decided to change to SMTP Relay to my providers SMTP Server.
But: my provider seems not to accept the submitted user information from relay_password. Every send request is not successfull because "UNKNOWN USER" (which is for sure unknown - because my "local" Zimbra User)
Even when I entered the correct User in relay_password he doesn't accept.
So I decided to use gmail.com to forward all my emails.
Gmail needs TLS - ok no problem - configured and finally emails are sent through gmail. BUT: all emails are sent as "firstname.lastname@example.org" (entered in relay_password) and not from original MAIL FROM.
Do you have an idea how to solve my problem?