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See if there is any help here
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If not post in this forum for better results
Note that your post reveals someone's email address.
Have you tried searching for the error message? E.g. (I've screen OCR'd your image text for you...)
A unique identity matching the From address was not found
"A unique identity matching the from address was not found" and folder flags. | Thunderbird Support Forum | Mozilla Support
Seems to be very specific to program settings somehow, so the Thunderbird forum is the place to pursue this.