FAQ - Public Key Certificates

FAQ - Public Key Certificates

Why is my digital signature in Adobe Acrobat INVALID?
I need to be able to digitally sign things, what must I do?
Why can I not select my work email address in the RA-Portal?
Why do I always get the Windows Security popup "Credential Required" when trying to sign a document?
Why is my digital signature in Thunderbird "Not Valid"?