some on our users receive the following error
Your message did not reach some or all of the intended recipients.
Subject: test again
Sent: 12/28/2015 12:55 PM
The following recipient(s) cannot be reached:
'---------@gmail.com' on 12/28/2015 12:55 PM
550 5.7.1 Unable to relay
However other users are able to send successfully to the same id/domain.
is there any need to reconfigure the connectors to solve this issue