Error during installation: “SQL Server does not exist or access denied”

I’ve followed the instructions (except for the PS script) from this post here: https://solidcp.com/forum/question/error-sql-server-does-not-exist-or-acces-denied/

I’ve enabled the browser service and set it to automatic, made sure it was running. I’ve restarted all the services, tried changing the authentication to mixed mode. Tried using Windows Authentication and the other option (putting my user/pass in) I’ve tried using “localhost\MSSQLSERVER”, tried using the IP/MSSQLSERVER and just the IP and just the MSSQL instance name. Nothing seems to work.

My best guess is that I missed something during the MSSQL 2016 installation but I installed ALL the options during the install.

Has anyone else run into this? Should I downgrade to a different version of MSSQL? Is there an updated PS Script to install SolidCP like in the link above?