Impact

Sophos is receiving reports regarding inbound email delays, from Sophos Central Email users using Exchange Online.

Inbound email from external senders are being stuck as "Queued for delivery" on the Central Email dashboard. Email issues are not being accepted by Office 365 at this time due to "Server busy"

• <email-ID>: host <yourdomain>-com.mail.protection.outlook.com[x.x.x.x] said: 451 4.7.500 Server busy. Please try again later from [y.y.y.y]. (AS780082) [CY1NAM02FT049.eop-nam02.prod.protection.outlook.com] (in reply to end of DATA command) 

What to do

Please reach out to Microsoft Support for further troubleshooting and options.

Workaround

1. Please ensure Exchange Online Protection is disabled in Office 365 as per our setup guide:
   • https://docs.sophos.com/central/Customer/help/en-us/central/Customer/concepts/configure365.html
   • https://docs.sophos.com/central/Customer/help/en-us/central/Customer/tasks/bypassingexchange.html
2. Bypass the following IPs:
   • US (East)
     • 18.220.12.142
     • 18.216.7.10

Next update

This article will be updated when more information becomes available.