I'm a bit stumped been working on trying to fix this issue for a few days now and decided it's finally time for help.
Essentially, I setup a new Ubuntu 16.04LTS server used to host my Joomla intranet site. It's running PHP7.0, Apache2, Postfix (For sending emails only), MySQL Server, pretty much the whole lamp stack. I have an internal exchange server which I inherited as I just started this job about two weeks ago and was provided no info on the servers.
I'm trying to get Joomla and by extension the ubuntu server to talk to the exchange 2016 server for email relay. When using Joomla's SMTP function and plugin the details, it fails to find the SMTP host. To test this I connected Joomla to my gmail account via the SMTP option and it was successful. The PHPMail function says it sends the email, but there's no email in the inbox.
I've already added the correct domain name and relay host in the postfix main.cf but I've got no luck. Any help would be appreciated.