I currently have a Hybrid setup with Office 365 with students in the cloud and teachers On-Prem. Lately i have been noticing issues with O365 users sending emails to On-Prem. O365 Mail can sometimes take up to 2 hours to 2 days to be received On-Prem.
I have opened a ticket with Office 365 Support and they believe the error is "When Office 365 try to send the email to on-prem, the “Defer” happened with the error {LED=450 4.4.317 Cannot connect to remote server [Message=451 4.4.0 Socket error ConnectionReset]"
They are unable to continue to resolve my issue because its a Hybrid scenario.
Any help would be appreciated.
