Our LMS (learning management system) software for the University generates emails between the professors and students via smtp relaying. I have configured a local server and can use smtp relaying to send files from the server to mailboxes - so we know the configuration is correct. However, when we try to relay from the LMS software (off site vendor) we get the "SMTP 550 5.7.60 SMTP; Client does not have permissions to send as this sender"
We found this article:http://o365info.com/smtp-relay-in-office-365-environment/ which indicated that if we created a security group in Office365 and used group delegation to give the account configured in the smtp relay send as permissions it should work. We did, but it doesn't. We then tested this further by selecting a single professor's account and giving the relay account send as permission directly, and it worked. To recap, if we assign "send as" rights individually it works, but in group it does not.
Do I have to visit everyone of out 1000+ mailboxes and do this configuration manually or is there a way to apply this change directly to all accounts or via the all group? Thank you in advance for your help.
Director of Information Systems
Kansas Wesleyan University