Not sure what release of Office 365 you're using? Go to the following Microsoft website:
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 messagesKnowledge Base articles
Users receive Send/Receive error messages after they configure multiple accounts in Office 365 by using Outlook
You can't send email messages in Office 365 Small Business from a domain that's set up for full redelegation
Still need help? Go to the Office 365 Community