Inserimento firma: Operazione non riuscita perché è stato riscontrato un errore sconosciuto

Hi @Angelo24328805lc30 

Hope you are doing well.

As per the issue description that the adding signature is showing the above error. Kindly try these troubleshooting steps:

1.Try to add a signature on a file from https://acrobat.adobe.com if that works then follow the steps below:

2. Check if the app is up to date.

2. Try repair installation from the help option from the menu bar. (For windows only)

3. Try resetting preferences. Refer this help article for the same: https://community.adobe.com/t5/acrobat-discussions/how-to-reset-acrobat-preference-settings-to-defau...

Let us know if that helps.

Thanks,

Harsh