There is no problem with the document, because when I try to verify the digital sign on the document before, it succeed. However, I don't know why this time when I try to verify the document, it indicates that the validity of the ocument is “UNKNOWN”. I have already tried the following troubleshooting tips listed on my school's website, but still does not work. Could anyone help me? I am very urgent to verify my degree dipolma. Thank you so much!!!
I am using the latest version of Adobe Acrobat Reader DC on Macbook.
I am connected to the internet as the Blue Ribbon does not work when offline. Adobe must communicate with servers to authenticate the embedded certificate in the transcript.
Adobe Reader Preferences must be up to date. Adobe Reader is sometimes set up with more stringent security settings , which could result in Global Sign CA not being on the list of trusted certificates. To make sure Trusted Certificates are up to date in Adobe Reader, use the Main Menu navigate to EDIT/PREFERENCES/TRUST MANAGER and check the boxes Load trusted certificates from Adobe AATL server and Load trusted certificates from an Adobe EUTL server. Click Update Now for both certificate types. Click OK to exit.
Security digital signatures and esignatures