Error when importing template to a report definition - Data management

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I am trying to load a custom template to a report definition in Data Management but receive an error (see screenshot). The template I am trying to load is in rtf format. I have tried to export one of the existing, out of the box templates and re-import to see if it was just an issue with my template, but I got the same error. My coworker is also getting the same thing. Any ideas?