This has been asked recently:
I have default user works with Release Manager in Client 100. I now want to create another user/client to work with Release Manager.
1. Login in Client 0/UC/UC: Create a new user and client, please make sure that the new created user assign to the correct client with full permission and authorization.
2. Go to the ARA Server, edit the customer.config file:
Add the following line into the the connection field below according to the new user. In ARA version 12 it looks like this:
Note: Each client should have an separate ARA database, else it will cause the inconsistent between ARA and AE. In the image above, I used database : ARA2 for the client 1985 and ARA for client 100.
3. After that you have to register this user into ARA database, by using the createuser.ps1 (located in: C:\Automic\Tools\ARA\Utilities\ImportExportCLI)
4. After finish, you can try to login in ARA with the new credential: