Office 365 - Get help when email messages will send but can't be delivered

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:

Code 4.4.7

Code 5.7.12

Code 5.1.10

Code 5.7.124

Codes 5.1.1 through 5.1.20

Code 5.7.133

Code 5.4.1

Code 5.7.134

Codes 5.4.6 through 5.4.20

Codes 5.7.13 or 5.7.135

Code 5.6.11

Code 5.7.136

Code 5.7.1

Codes 451 5.7.500-699 (ASxxx)