Office 365 Mail Flow Troubleshooter

The Office 365 Support team has just released a guided mail flow troubleshooter here:

If you have users complaining that mail delivery takes too long, or that mails are remaining in their outbox, or that recipients are not receiving e-mails at all; the guided walkthrough will step you through the troubleshooting steps required to diagnose and resolve the problem


Access the troubleshooter here:

For your reference, the following diagram shows many of the components involved with mail delivery from sender to receiver, any of which could be interfering with your email arriving: