Below are the steps to switch the authentication mode:
1

1. Access qcsiteadmin_db schema;
2. Select the PARAMS table;
3. Change the PARAM_VALUE from ''LDAP'' to ''QualityCenter'' for the PARAM_NAME ''AUTHENTICATION'';
4. Restart the QC/ALM service or reboot the server machine.

Note: If the database schema cannot be access, please consult with the responsible DB Administrator

UPDATEPARAMS

SETPARAM_VALUE='QualityCenter'

WHEREPARAM_VALUE='Ldap';