We have an Exchange 2007 user that needs to use IMAP. It's been set up on his Outlook 2007, but we are finding that he is unable to send mail externally with the following bounceback error:
550 5.7.1 Unable to relay
Sending to internal addresses work fine. The only way around it was to create a new receive connector with the following details:
- allow port 587 to receive mail
- Enable the connector to receive mail from his public IP (as he is a remote user, he has no other access to the network).
As his public IP is not static, once it refreshes to something else or he tries to access IMAP from another location (he uses a laptop), he will lose the ability to lose send externally again.
My question is, what is the permanent fix to enable users to send via IMAP? I do not believe that Exchange can only use a IP based authentication system, there must be another way?
Thank you for your help in advance.