Currently I am having a difficult time receiving inbound email. Currently, the environment that I am conducting mail tests looks as follow....
Server1(mail server) --> Server2(SMTP Antivirus Gateway server) --> Server3(mail server)
All of the server are currently under the same domain. When I send an email from Server1 to Server3, it would work fine...But when I send an email from Server3 to Server1, Server1 would not receive the email and Server3 would get a email from the SMTP server(Server2) states as follows...
Mailbox unkown or not accepting mail.
In the "detail.txt" file that is attached to the error email, it would read as follows.
Cannot route mail to user
I have tried to reply back on the email that was sent from Server1 on the Server3, but it would still give me this error email. Please point me to the right direction to correct this issue.