From my last post, http://coffeeandsql.com/2013/11/10/70-457-reviewer-15-implement-database-mirroring/, you were able to successfully setup a database mirroring. For further monitoring and checking if everything is OK, you may use the following T–SQL statements.
To check the principal id the database mirroring is using;
SELECT name, principal_id FROM sys.database_mirroring_endpoints;
This principal id should be the grantor when you run the query below
SELECT EP.name, SP.STATE, CONVERT(nvarchar(38),suser_name(SP.grantor_principal_id)) AS GRANTOR, SP.TYPE AS PERMISSION, CONVERT(nvarchar(46),suser_name(SP.grantee_principal_id)) AS GRANTEE FROM sys.server_permissions SP ,sys.endpoints EP WHERE SP.major_id = EP.endpoint_id ORDER BY Permission,grantor, grantee;
You need to find the domain account your SQL Server service is using here. If not you will need to transfer this ownership to the SQL Server service account. To do so, you may run the T-SQL statement below
ALTER AUTHORIZATION ON ENDPOINT::Mirroring TO [domain\serviceaccount]
Your configuration should be completed at this point and running smoothly. For more on troubleshooting other issues with your setup, you may visit http://technet.microsoft.com/en-us/library/ms189127.aspx