Need to connect to a remote instance, via TCP. This is a named instance in a cluster. I've tried every combination that I can imagine with no success:
-serverinstance servername\instancename - (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
-serverinstance servername\instancename,portnumber - Invoke-Sqlcmd : Value cannot be null.
-serverinstance IPadress:portnumber - (provider: SQL Network Interfaces, error: 25 - Connection string is not valid)
-serverinstance tcp:IPadress:portnumber - (provider: TCP Provider, error: 0 - No such host is known.)
Can you help?