(Solved) Error: Changes to the state or options of database '' cannot be made at this time. The database is in single-user mode, and a user is currently connected to it.

Error:

Changes to the state or options of database '' cannot be made at this time. The database is in single-user mode, and a user is currently connected to it.

Solution:

ALTER DATABASE [dbname] set multi_user
 
SELECT request_session_id FROM sys.dm_tran_locks 
WHERE resource_database_id = DB_ID('[dbname]')
 
KILL [session_id]