at least one signature has a problem

[Yiming Zhang]

recently all the sudden after I e-sign a pdf file on the signature panel it always shows a message "at least one signature has a problem" at it says that signature validity is unknown and it has not be included in the list of my trusted identities. How can I fix this problem?

[Rijul Raj Khurana]

Hello Yiming,

Was the PDF file used got tampered in any way? Is it possible to share the original file via message?

Regards,

-Rijul