WE have issue a weird issue. Something to do with permissions most probably.
Have an ASP website that uses forget password feature for members to send them new password.
The domain user who has mailbox and can send and receive email is coded into the website and port used is 2525 for SMTP. We receive the message : Mailbox unavailable. The server response was: 5.7.1 Unable to relay
When try to send to a user who is not part of our domain or is not internal user. But if we reset password who has internal mailbox or is part of domain it works fine.
But here is the tricky bit. IF we give this user enterprise admin permission, the relay is not a concern. Seems like it works fine. So same user with normal domain user access cannot dispatch the reset password email to external mailboxes but can when he is enterprise admin. I cannot figure out where or what role/permission needs to be given to this user so he can be taken off the enterprise admin group but still relay emails via the smtp exchange server.
WE are using exchange 2013 server.
Any assistance or direction would be great.
Cheers