I use CIVI to send newsletters for my organisation. When the receiver opens the newsletter in the outlook app or on a mac they receive an error message. It seems to work for those opening the newsletter in Office 365 and through their browser as it doesn't appear.
The error message or error image appears as a sort of trace for the drafting of the newsletter. Where I have deleted an image or a text box in editing the newsletter, that's where the error appears.
Would really appreciate any take or tips on how to fix this!