Forum Discussion
your message couldn't be delivered
Hi experts
A user from external domain(user@extdomain.com) has sent an email to one of my office365 user(myuser@contoso.com).
user@extdomain.com got the below NDR. Experts help me in troubleshooting this issue.
Your message to myuser@contoso.com couldn't be delivered
Security or policy settings at contoso.com have rejected your message
- Looks like you’ve blocked the external domain! Check the exchange online settings!
