When attempting to enroll a PGP Desktop client with the PGP Universal Server you receive the following error:
Unable to enroll with an error of invalid License number error code 11993
This issue can occur when using LDAP Directory Synchronization for enrollment and the user LDAP attributes do not match the LDAP attributes for a custom policy.
When the user's attributes do not meet the custom policy attributes, the user is placed in the Internal Users: Default policy group or Excluded Users if the option is set to Exclude non-matching users by default on the Internal Users: Default policy Directory Services tab.
The error then occurs if the Internal User:Default policy does not have a license for PGP Desktop.
Here are some areas to investigate to troubleshoot the issue:
Check the license