Cannot sign with CAC card

++Adding another observation to my last post,

Have you or the user created a self-signed certificate before ?

Hi @James3434004317d7 ,

Just a few quick observations:

• Your screenshot contains PII. You should blurr out those PII elements
• Also, just for troubleshooting purposes, if this PDF wasn't downloaded from a trustworthy source the official website to download this PDF is at : https://www.esd.whs.mil/Directives/forms/dd2500_2999/DD2875/
• Can't tell from your screenshot if you are using a personal computer (looks like though) or a DoD approved computer
• Seems like you're on Microsoft Windows 11
• try unplugging the USB smart-card reader and plugging it back to a different USB port on that computer

In any case, if this is a work computer, I've seen this error pop daily when a primary user is signed in to the computer but other users are also piggybacking an additional USB smart-card reader on the same computer (to sign documents or open web browser sessions to check emails and such).

When multiple users do this, the main digital certificate that may appear first from the list of digital certificates usually is for the primary user who is signed in in that computer or for another person that was using the same app before you.

This may explain why you are not able to use your updated CAC with a new digital certificate because the old one is still showing in the list of signers.

Since you've mentioned about your updated CAC, you may need to delete the old digital certificate from the certificate store. See Microsoft guidance below:

• https://answers.microsoft.com/en-us/windows/forum/all/removing-old-digital-certificates-in-windows-10/57c18bb4-eb03-4f56-ab19-5d00a96e4995  (<<== this guidance is for Windows 10 but may work with 11 versions)

Verify if this is your case.

It may be necessary that you remove first the old digital certificate(s) that were previously associated with your old smart card (or somebody else's), in which case you may also need to update the Adobe Approved Trust List (AATL):

• https://helpx.adobe.com/acrobat/using/trusted-identities.html#manage_trusted_identities

Also see link below for more information:

• https://militarycac.com/windows11.htm

All of the last steps above may not be entirely necessary but these are things that I would check to be thorough. After you're done troubleshooting, try again. You should be able to sign PDFs with your current CAC.