Assume that you use Always On availability groups (AG) in Microsoft SQL Server 2014, 2016 or 2017, and there is one node that's not reachable in a cluster. For example, you add an incoming firewall rule to block TCP port 135, 137, 139, or 445.
In this scenario, when you install an instance of SQL Server in the cluster, the SQL Server installer scans all cluster nodes for a duplicate instance name. If any of the other cluster nodes are unreachable, the installation is unsuccessful.
The fix for this issue is included in the following updates for SQL Server:
This fix adds a new SkipRule switch to bypass remote node discovery. To add this switch in a SQL Server installation, use the following format:
setup /SkipRules=Cluster_VerifyForErrors_Instance_Name /ACTION=Install
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.