Hello support, I don't want to be an hassle to you neither pose useless questions but this is my last resource before leave my problem unsolved, so i really hope you can help on this. As per subject I am trying to install add on GMX mailchecker 6.5.5 to Firefox release 95.0.1 (which i like most and don't like to change) but any time I try i get the error "the add on appears to be corrupted" - this happens also when I try to install themes (but it is not a big problem to me i like also your standard design) and any thing else. Now I switched to a gmx mail account also because i saw the option to have an add on for firefox (saying to be compatible with version from 46 onward) but I cannot solve how to install it correctly. When loaded as a temporary add on in debug mode it works really well but then on standard mode i cannot get to have it working. So far i have tried to -reinstall Firefox -install add on from a file -disable mandatory signature in advenced configuration -disable malware scanning while installing the addon BUT none of them worked in my situation. I believe there is an easy way of having it working and seeing it from the debug mode it seems also well integrated SO where am I wrong? Could you please advice me on how to solve this problem I am facing? Thanks a lot for your help, you understand i am not up to date with new web oriented programming but hope this doesn't matter much. (as a feedback for you: if you wonder why I want to stay with FFox 95 it is because I don't need ai features and dislike emoji ... otherwise your browser is excellent -still have a firefox 1 executable in my hard drive... still open it sometimes... ) Best regards, Filippo