Avatar of Sunny
Sunny
 asked on

External gmail sent to one user with know good address "550 5.1.1 User unknown" We recent migration to Cloud Office 365.

Recent migration to Cloud Office 365.

Test to self - OK
Test to external gmail address - OK
Reply from that email ...

Mail Delivery Subsystem <mailer-daemon@googlemail.com>
10:32 (41 minutes ago)
to me

Error
Address not found
Your message wasn't delivered to zzzzzz@zzz.com because the address
couldn't be found or is unable to receive email.
The response from the remote server was:
550 5.1.1 User unknown




Microsoft 365Outlook

Avatar of undefined
Last Comment
David Favor

8/22/2022 - Mon
ASKER CERTIFIED SOLUTION
David Favor

THIS SOLUTION ONLY AVAILABLE TO MEMBERS.
View this solution by signing up for a free trial.
Members can start a 7-Day free trial and enjoy unlimited access to the platform.
See Pricing Options
Start Free Trial
GET A PERSONALIZED SOLUTION
Ask your own question & get feedback from real experts
Find out why thousands trust the EE community with their toughest problems.
I started with Experts Exchange in 2004 and it's been a mainstay of my professional computing life since. It helped me launch a career as a programmer / Oracle data analyst
William Peck