Hello!
Can you share more details so we could help you?
1. If you select Multiplayer > Display list of hosts, do you see a lot of servers? If you do not see any servers, have you changed any filters? If you have set "Private - yes", "Public - no", you might not see any on the list.
2. If you select a host and then select "GO" what happens? Do you get any error messages?
3. It would be great if you could share any details/screenshots of any errors that you might be seeing.