Ortho System should be allowed to communicate through Windows Defender Firewall. This should be allowed automatically during the installation process but in case of permissions issues, there might be a need to do it manually.
MSSQL executables that should be added to the whitelist:
C:\Program Files\Microsoft SQL Server\MSSQL11.ORTHOSYSTEM\MSSQL\Binn\sqlservr.exe
C:\Program Files (x86)\Microsoft SQL Server\90\Shared\sqlbrowser.exe
Then I went to the Windows Defender Firewall >> Allowed applications settings and added the above paths to allowed applications.