This article contains links to technical resources and support information for troubleshooting mail flow in Office 365.
To troubleshoot common mail flow issues in Office 365, see the Mail Flow Guided Walkthrough. The walkthrough helps admins to diagnose and resolve issues that are related to mail flow in various scenarios.
Before you review the resources in this article, be aware that the Microsoft Remote Connectivity Analyzer offers several tests on the Office 365 tab that are helpful when you are troubleshooting mail flow in Office 365. These tests include the following:
Office 365 Exchange Domain Name Server (DNS) Connectivity test
Inbound SMTP Email test
Outbound SMTP Email test
The following resources discuss mail flow.
Cannot send email messages
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