Digital Sender CAC Authentication Error

[aird88]

I am troubleshooting a HP Digital Sender 9250c and I am using a CAC reader to encrypt emails with certificates from a smart card. I'm not sure why its doing it but everytime I place the smart card in the reader and punch in my pass code I get the Authentication Error. I know my passcode is legit since I use a smart card to login to other computers. Please help because I cannot find anything online to help resolve this issue.

 

[aird88]

Ok, I left the computer unplugged overnight. Plugged it in the next day and tada its working again. I love how some things magically fix themselves. Any ideas on what may have caused this so I can prevent it from happening again?