SSL user failed to logged in due to no_matching_policy

I have an intermittent issue where some users cannot log into the corporate network using FortiClient.  They get an error stating: 'Unable to logon to the server.  Your user name and password may not be configured properly for this connection. (-12).'

At the FortiGate, I get an 'ssl-login-fail' error stating that 'SSL user failed to logged in' error.  The Reason is: 'no_matching_policy'

This issue is seen with a local user and AD user.  The same user can login one day and not the next.  While some users can login I have others, at the same time, who cannot.  I have made sure that the LDAP user has no special characters in the password - since this was a known bug in the past.

Any ideas would be greatly appreciated.