Troubleshoot email issues
When you run into problems with email, these resources can help you solve email connection and delivery problems.
First, check out these Outlook troubleshooters.
There you'll find top solutions to email issues, frequently asked questions answered by the Office team, the US support number, and a section where you can email us about your specific problem.
Look up help by error code
When Office 365 can't deliver email you sent, you'll receive an email notification called a non-delivery report. Find your error code for specific help with getting your email delivered:
|Codes 5.1.1 through 5.1.20
|Codes 5.4.6 through 5.4.20
||Codes 5.7.13 or 5.7.135
||Codes 451 5.7.500-699 (ASxxx)
Additional email help
If you're using Office 365 operated by 21Vianet in China, please contact the 21Vianet support team.