Can someone help us if you have any idea on how to fix the issue with our O365 to On prem . Can't send email from 0365 to on-prem vice versa after we successfully setting up hybrid configuration wizard.
Here’s the summary Report on the issue;
Main issue: Unable to send email from O365 to Exchange 2016 On-Prem and vice versa after successfully setting up hybrid configuration wizard.
List of mitigation process have been tried so far:
• As suggested by Microsoft we changed the accepted domains in Exchange Admin Center from relay to authoritative.
• NAT rule creation in Sophos UTM.
• Adding a new UPN suffix domainl.com to the domain controller.
• Opening a ticket to microsoft and sophos.
• Reinstallation of hybrid configuration wizard to another exchange server.
• Reinstallation of the exchange certificate to exch01 and exch02.