Window Errors
The encryption attempt failed because no valid certificate was found

Error 781 is an Internet Explorer error which occurs when you have certificates enabled for Internet Explorer 5.0. To resolve this error, follow the instructions below:

Go to Start, then Settings, Control Panel. Double click on the Internet Options button.

Click on the Content folder

Click on the Certificates .. button

Click on the Advanced button

Ensure that Client Authentication is NOT ticked

Click OK and then OK to finish