ORA-01921 when configuring Oracle Enterprise Manager

Configuring Oracle Enterprise Manager on Oracle 11g through command ’emctl -config dbcontrol db -repos create’ may sometimes lead to error ORA-01921

Go through the following steps to resolve this issue.

1. In sqlplus :
   drop user sysman cascade;
   drop public synonym SETEMVIEWUSERCONTEXT;
   drop role MGMT_USER;
   drop PUBLIC SYNONYM MGMT_TARGET_BLACKOUTS;
   drop user MGMT_VIEW;
2. emca -deconfig dbcontrol db
   emca -config dbcontrol db -repos create