Invalid credentials when digitally signing error

Hello,

I get an error of "Invalid credentials when digitally signing" with new CAC card on windows 10 SHB using Adobe 2015 DC. If a user with an older CAC logs into this system they can sign pdf's but the user with one week old CAC gets the error. I have uninstalled and reinstalled Adobe 2015 DC ActivClient 7.1 and installed the newest Root certificate v5.2. No joy.

Please help.

JP