Topic Tags: Toolset Blocks
When editing a Content Template you could see an error ‘Something went wrong while fetching the dynamic content from the selected source, with message: “Sorry, you are not allowed to do that.”‘.
The blocks in the template will also show messages about failures with dynamic sources.
When you edit a Content Template at the top it has a selector for which post should be used as a preview while designing the template.
This error occurs if the post that had been being used for the preview is subsequently deleted.
The workaround is simple enough, but not obvious: choose a different post to preview the template with.
This will be fixed in an upcoming update.