Puntuado con 5 de 5 estrellas

Very useful.

Esta valoración es de una versión anterior del complemento (4.0.0). 

This sounds like a known problem. You can get a fixed version from https://github.com/lieser/dkim_verifier/issues/279#issuecomment-997386893.

Next time please don't use the reviews to report problems. Use https://github.com/lieser/dkim_verifier/issues or write me an E-Mail (in English or German).
See also https://addons.thunderbird.net/en-US/review_guide