title: Digital Signature/ eSign verification fails
body: <p>I have a eSigned / Digitally signed PDF, the document is signed  using iText lib in detached signature. I am having issue while verifying the signature, getting message "signers identity is invalid because it has expired or not yet valid" and in signer info "There were errors building the path from signers certificate to an issuer  certificate."</p>
  
  <p>I have tried many ways to validate the signature but couldn't get any success. If I explicitly add signers certificate as trusted certificate then I get a green check and able to verify the signature but I think  thats not the correct way to do it.</p>
  
  <p>Adobe Signature setting are as follow:-
  <a href="https://i.stack.imgur.com/923kM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/923kM.png" alt="signature verification preferences"></a></p>
  
  <p>digitally signed pdf can be found here<a href="https://drive.google.com/file/d/1_p4l1pjzGEtZOKhX8hS97Gv1wSj9FmXx/view?usp=sharing" rel="nofollow noreferrer">digitally signed document</a></p>
  
  <p>can anyone please help to resolve this issue.</p>