SQL: Cannot execute as the database principal because the principal "dbo" does not exist

Cannot execute as the database principal because the principal "dbo" does not exist, this type of principal cannot be impersonated, or you do not have permission. (Framework Microsoft SqlClient Data Provider):

• Server Name: server_name or IP
• Error Number: 15517
• Severity: 16
• State: 1
• Line Number: 1

Resolution: ALTER AUTHORIZATION ON DATABASE::[YourDatabaseName] TO [sa];