If you receive a "Save Failed" error message while using the email builder, it's likely being caused by a troublesome content block. This most often occurs if a content block has lots of mixed text formatting, or an image that is unable to save successfully. Finding and editing this content can usually resolve the issue.

How to troubleshoot a failed save

To find out which content block is triggering the error message, you can try the following troubleshooting steps:

1. Create a copy of the campaign.
   
2. Edit the campaign.
3. Delete content blocks from the bottom up to identify which content block is causing the issue. You can add the content blocks back in later by clicking Undo.