Hello.
i have an issue when configuring Exchange hybrid deployment in my environment.
when i complete the Exchange hybrid wizard and OAuth is finished our exchange environment will not receive emails from the "internet" as in senders outside the company.
mail will can be sent out and will flow between internal users.
when i check the message trace on 365 the emails were failing with the following error.
Users were also getting a bounce back saying
Diagnostic-Code: smtp;550 5.4.1 [user@domain.com]: Recipient address rejected: Access denied
i wondered if it had anything to do with the MX record on our public DNS, i changed this to the one recommended by O365 domain DNS assistant, but this made no odds,
it looks like it could be a receive connector issue however i am new to exchange so i am still learning.
the only way to fix the issue was to run Remove-Hybridconfiguration on the Exchange 2013 server, when this finished and few moments had passed mail began being received from the internal again.
Any Suggestions on what could be caused
many thanks