Customers Using Custom SMTP Server May Be Seeing Email Delivery From TDX Email Services

Update timeline

1. identified Oct 25, 2023, 02:39 PM UTC

   We have recognized an issue where customers that have configured their work management instances to use a custom SMTP server may be seeing email fail to deliver via the custom SMTP server, with subsequent successful delivery via the TDX email services. This appears to be due to IP addresses in the list defined here (https://eus-app.teamdynamix.com/meta/) being included in lists maintained by Spamhaus (https://www.spamhaus.org/) which some customers are using to block inbound SMTP traffic. If the ability to bypass Spamhaus checks exists for your email infrastructure, we would recommend explicitly bypassing the Spamhaus checks for TDX IP Addresses (https://eus-app.teamdynamix.com/meta/).

2. identified Oct 25, 2023, 02:41 PM UTC

   We are continuing to work on a fix for this issue.

3. monitoring Oct 25, 2023, 03:16 PM UTC

   We have removed all TDX IP Addresses from the Spamhaus SBL, but are still noticing custom SMTP servers blocking email delivery due to Spamhaus blocks. It is our assumption that customer SMTP servers are caching the Spamhaus block list and that it could take some amount of time for the cache to be updated, allowing the blocking to cease. Email delivery is still occurring in the cases of Spamhaus block via the fallback TDX email services.

4. resolved Oct 25, 2023, 03:33 PM UTC

   Our logs indicate that outbound email from TeamDynamix is no longer being blocked by Spamhaus as of 11:26am ET.