When you use Office365 as your Mail Server the messages will come into JIRA and you can setup JIRA to create issues automatically per Creating issues and comments from email. In light of this you may not need to create the connection from O365 to JIRA since JIRA can handle this for you and you can tell your add-on to use the mail server JIRA uses.
In addition, take a look a look at the following Community post:
Hopefully this helps.
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG
We're bringing product updates and pro tips on teamwork to ten cities around the world.Save your spot