[2020] Cant join local dedicated server while hosting on separate machine

Glad you managed to solve the problem.
On the Dedicated Server Launcher top post there’s a list of things that can cause issues:

If despite everything you still cannot get through, make sure that you do not have a firewall somewhere configured to block everything.

Generally when I try to track this type of problem:

• I make sure that my machine is fully updated
• Than no other software than what I need is running
• I disable the firewall
• I tweak the network issues until it works
• If it works, I enable the firewall again
• If it stops working then I investigate firewall rules (inbout/outbound rules, ports, etc…)

Firewalls are useful, but when diagnosing, the less moving parts, the better chances you find the issue fast.