You receive an error "Validation Failed. Check fields for validation errors" when attempting to add a New User login for Enforce, but there are no errors shown in any of the fields. This occurs when Enforce is configured to use AD(Kerberos) Authentication for login.
A combination of factors lead to this situation.
When using AD (Kerberos) Authentication, the password complexity is taken care of by Active Directory, and DLP does not need to be configured to "Require strong password" or have non-default settings in their passwordenforcement.properties file.
To resolve this issue, you can either uncheck the "Require strong password" setting, or revert changes to the passwordenforcement.properties file so that it is back to default.
After doing so, you should be able to add a new user without the validation error.
Symantec/Broadcom is planning on addressing this issue in a future release so that this situation does not result in the validation error.