In our Quality Center 12.6, LDAP setting is set to "Use default values for" "Active Directory". But now I would like to add some new users that authenticated locally by QC. Can this be done?

When trying to login to HP ALM all users receive the following error(image attached).This is causing a total loss of service. Error says:  "Failed to Login. Please contact system administrator for help.  Description:  Authentication failed.  Verify your user name and password." Site admin is also gi...