Lets say i have 4 server's in my SharePoint farm. All the servers in the farm are configured to use a SQL alias "ProdEnv". If i want to add a 5th server in the farm, can i have a different SQL alias just for this new server? Lets say "ProdEnvDR"
In SharePoint farm, alias concept is relevant only with SQL server... what happens in SQL server? There might be multiple SQL servers for SharePoint that will be mapped and connected with the SQL availability group listener for the server stability and finally with this listener name SQL alias name is mapped.
Why does the SharePoint server connect to fail in SharePoint config database while running the wizard?
There could be multiple scenarios for this -
First, we need to check network port connectivity between the new SharePoint server what you are trying to add and the SQL server.
Check whether if any firewall is blocking to access the SQL server, the best way to handle this, talk to your network team, they will assist you.
Make sure TCP 1433, 32843, 32844 is opened in the new SharePoint server.
Finally, verify that the SharePoint_config database is connected both the primary availability group and secondary availability group because when you are running the wizard and passing the alias name we are not directly talking to SharePoint server, it is going through some layers of connectivities, so the connectivity has to pass through.
For the various TCP/IP Port refer to the below article:
For the SharePoint server cannot connect to the SQL database, refer to the below article: