Connect to server

Hi,
I’m new on Unity and sorry if someone already asked the question,

I would like to connect to a server external of Unity with localhost. I saw few post with mirror but I can’t connect the client to my server.
So I don’t know if mirror is the appropriate solution for me.

Thank you in advance for your help

You haven’t mentioned what the purpose of the server is, so hard for anyone to say what solution would do well for that purpose.