SaaS

Office365 blocking mails from cloudv.spamtitan.com / 18.188.207.172

For those SpamTitan Cloud customers using cloud11/cloud12.spamtitan.com as their MX record, Office365/SpamHaus.org were blocking emails from cloudv.spamtitan.com (18.188.207.172) between about 12:30 AM GMT and 2:30 PM GMT.  

Priority 1

Updates

4 Mar, 2023: 14:45 GMT/09:45 ET US
We submitted the delist, and it was immediately accepted:

DNS/MXtoolbox.com shows the IP address removed from SpamHaus (SpamHaus/cloudv.spamtitan.com check)

Office365 was still blocking , and referencing spamhaus at this time.  We have already configured cloudv.spamtitan.com to not accept any mail, so it will flow though cloudw/cloudx.spamtitan.com (which are not blocked) 

04 Mar, 2023 15:45 GMT/10:45 ET US

We confirmed Office365 and SpamHaus was not blocking anymore, and had already opened up SMTP Port 25 to cloudv.spamtitan.com.

Further Information:

You may see rejected/bounced emails as:

1) Delivery Status = Bounced, or

2) Invalid Recipient (If using Dynamic Recipient Verification, Office365 was rejecting the RCPT TO probes).