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 address.  This bypasses our IP address from Office365 spam checks (which is advised idea 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

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).