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 | SaaS |
Priority 1
Office365 tenants are deferring messages with the SMTP Response "451 4.7.500 Server busy." for customers using:
Summary
Office365 tenants are deferring messages with the SMTP Response "451 4.7.500 Server busy." The best way to
The best way around this -throttling- is to create a "Partner Organization to Office365 Connector"
https://docs.titanhq.com/en/2319-locking-down-your-office-365-mail-server.html
The SpamTitan IPs are:
3.22.148.152
18.189.8.252
3.140.150.54
18.216.227.84
3.134.134.92
Impact
If this is not done in Office365, it may continue to defer messages with "451 4.7.500 Server busy." instead of accepting them immediately. Those that have the connector in place are not experiencing similar delays.
Update: Adding the connector so that Office365 treats the IPs like a partner, and doesn't think they are IPs that are trying to flood the client has stopped the "Server busy" for multiple clients.
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