your message couldn't be delivered

%3CLINGO-SUB%20id%3D%22lingo-sub-797866%22%20slang%3D%22en-US%22%3Eyour%20message%20couldn't%20be%20delivered%3C%2FLINGO-SUB%3E%3CLINGO-BODY%20id%3D%22lingo-body-797866%22%20slang%3D%22en-US%22%3E%3CP%3EHi%20experts%26nbsp%3B%3CBR%20%2F%3E%3CBR%20%2F%3EA%20user%20from%20external%20domain(user%40extdomain.com)%20has%20sent%20an%20email%20to%20one%20of%20my%20office365%20user(myuser%40contoso.com).%3C%2FP%3E%3CP%3Euser%40extdomain.com%20got%20the%20below%20NDR.%20Experts%20help%20me%20in%20troubleshooting%20this%20issue.%3C%2FP%3E%3CP%3EYour%20message%20to%20myuser%40contoso.com%20couldn't%20be%20delivered%3CBR%20%2F%3ESecurity%20or%20policy%20settings%20at%20contoso.com%20have%20rejected%20your%20message%3C%2FP%3E%3CP%3E%3C%2FP%3E%3C%2FLINGO-BODY%3E%3CLINGO-LABS%20id%3D%22lingo-labs-797866%22%20slang%3D%22en-US%22%3E%3CLINGO-LABEL%3EAdmin%3C%2FLINGO-LABEL%3E%3CLINGO-LABEL%3EExchange%3C%2FLINGO-LABEL%3E%3CLINGO-LABEL%3EHybrid%3C%2FLINGO-LABEL%3E%3CLINGO-LABEL%3EOffice%20365%3C%2FLINGO-LABEL%3E%3C%2FLINGO-LABS%3E%3CLINGO-SUB%20id%3D%22lingo-sub-797876%22%20slang%3D%22en-US%22%3ERe%3A%20your%20message%20couldn't%20be%20delivered%3C%2FLINGO-SUB%3E%3CLINGO-BODY%20id%3D%22lingo-body-797876%22%20slang%3D%22en-US%22%3ELooks%20like%20you%E2%80%99ve%20blocked%20the%20external%20domain!%20Check%20the%20exchange%20online%20settings!%3CBR%20%2F%3E%3C%2FLINGO-BODY%3E
Highlighted
Occasional Contributor

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

rej.JPG

1 Reply
Highlighted
Looks like you’ve blocked the external domain! Check the exchange online settings!