Is your user’s Outlook profile has specific CAS Server instead of CAS array name? When user creates a new Outlook profile, Outlooks reads the mailbox’s server name from the Exchange and AD and sets up automatically. You are wondering why the Auto Discovery finds a specific CAS server name, not the CAS Array name.
If Outlook profile server name is set to single CAS server name, then when happens that CAS server is down. That’s why we have to use CAS array name for the Outlook clients.
Answer is easy. It’s a manual settings on the database. If you create a new Exchange database, you have to manually setup the CAS Array name as RPC Client Access Server for the new database. Here is how we do it.
Type this command on the Exchange Management Shell:
Get-MailboxDatabase database_name | fl Name, RpcClientAccessServer
e.g., Get-MailboxDatabase MailboxDB1 | fl Name, RpcClientAccessServer
Check what the RpcClientAccessServer is set to. This is what Auto Discover will provide to Outlook. To change this setting, Type the following command.
Set-MailboxDatabase database_name -RpcClientAccessServer FQDN_of_CAS
e.g., t-MailboxDatabase MailboxDB1 -RpcClientAccessServer CASArray.company.com
You may have to set this to all of your mailbox databases. You can do that easily by
Get-MailboxDatabase | t-MailboxDatabase database_name -RpcClientAccessServer FQDN_of_CAS
