Summary of impact:

At approximately 06:30 UTC on Wednesday 26th October 2022, after a platform update, campaign previews containing Dynamic content and our Spam check feature failed to work for some campaigns. From approximately 12:44 UTC, previews not containing Dynamic content began to fail too.

All issues were resolved by approximately 13:30 UTC by rolling back the responsible changes.

This issue only affected previews and Spam check, meaning no other features were affected and sends continued as normal.

 Root Cause:

We made a change to a low-level personalization component that wasn’t compatible with previewing Dynamic content and Spam checks. Test sends and full sends that included Dynamic content continued to work as expected, however, campaign previews failed to load correctly and would’ve appeared blank.

Mitigation:

The timeline (in UTC) for resolving this issue was:

• 09:42: We identified the issue
• 12:42: We released an initial fix for the issue
• 12:44: We released a fix for an unrelated issue which unintentionally overwrote this fix, causing other previews to begin failing too
• 13:30: We released a secondary fix to resolve the issue.

Next Steps:

To prevent this issue reoccurring, we’ll:

• Extend our testing environments to allow for greater testing on our Spam check feature
• Review our QA process to make sure robust testing is done on these features to prevent this happening again in future.