SQL intergration error


We are moving to new domain and new cluster account been created for SQL cluster. There is 2 cluster account created for SQL cluster server, 1 for quorom and 1 for SQL server.

Both cluster server has been imported to DP cell manager, 1 SQL cluster account has been added to  SQL management studio under security and assigned serveradmin role. And also map as backup operator and owner for each database.

When try to modify current SQL backup, choose show all for the database, will get error message (attached screenshot).

So try to configure the SQL backup from fresh, after choosing the cluster server, DP GUI will hang (attached screenshot).

Please advise what is causing the problem. Thanks.