Date: 17 Apr 15:07 GMT/11:07 AM ET US

It has come to our attention that us3-smtp2.titanhq.com / 3.23.166.50 is being intermittently blocked by some Office365 Servers as a "banned sending IP", when it is actually not banned

Recommended actions:

1) Create a Connection Filter in Office365 for our IP addresses.  This bypasses our IP address from Office365 spam checks (which is advised anyway):

https://learn.microsoft.com/en-us/defender-office-365/connection-filter-policies-configure

These are our IP addresses to include:

3.145.228.208

3.23.166.50

18.219.82.30

52.14.176.194

3.143.188.200

==> this is Connection filtering, not the Partner Organization to Office365 Connector.

2) As per the delist request, it also does no harm to create a support ticket from your recipient tenant (since the delist doesn't think the IP is banned, only some servers).


29 Apr 23:00 GMT:  Update

The last "banned IP response" was from over 48 hours.  We still recommend to have the Connection Filtering Policy in place if you have it, and to create it if you haven't.