You try to restore a SQL database to Microsoft SQL Server 2017 with CU15 that supports AlwaysOn Availability Groups, but you are not able to select an availability group at the "Specify AlwaysON Restore Options" step.
ServerNetworkProtocolProperty is missing in CU15 for SQL Server 2017 VMI class. This class is used during the restore process.
In SQL Explorer log files, you can see the following record:
Failed to resolve TCP/IP port. Invalid class Missing class will lead to restore issues if the following is true: - SQL server is running on non-default (1433) port. - SQL Server Browser service is not running.
On the SQL Server, run the following command to recompile MOF files for the WMI SQL Classes: