Cryptographic key was not found

I have a mail-In Database which when a Help Request is sent to it, it gets there fine. Then if I try to save a form after editing it and I get the below error.

“Cryptographic Key was not found”

If I create the Help Request in the database itself and edit the request and save, it saves fine. So what field is it putting in there that gets input after it gets mailed to the mail-in database?

I really need help on this and any help is greatly appreciated.