fill and sign --> sign yourself

@Luciano_Capanna3201 ohhh, I wonder if this is a caused by a glitch in the software or a corrupted signature file. Try restarting Acrobat to see if that clears the issue. If not, you can try clearing the application's cache and temporary files. Sometimes, old data can interfere with the program's functions. If the problem persists, you may need to reset your Acrobat preferences to their default settings. This can often resolve strange behaviors caused by customized settings. Be aware that this will reset all your personalized settings in Acrobat, so you may need to reconfigure some options afterwards.

If none of these solutions work, you could try creating a new signature and deleting the old ones, or as a last resort, reinstalling the latest Acrobat.