I´m trying to sign digitally with my certificate (given by the Spanish Police Authority), and the message received is that the credential i´m trying to use is invalid.
it´s valid because i´ve signes documents with that (web application Valide from spanish gobernment, and is valid until 29 january 2020). but i need to sign a pdf document.
As per the description above, you are getting an error message that the current Credentials is invalid to sign the PDF, Is that correct?
Please refer and try the troubleshooting steps from the following KB docs which discusses the similar issue "the credential selected for signing is invalid"
Let us know how it goes.