Connect To Dedicated Server

Hi guys, I have a headless build on linux server and I run it success. When I connect server from terminal everything still ok. But when I set IP and port to NetworkManager in unity editor client can’t connect the server. After some minutes it throw exception “failed to connect server”. Do I miss something?
Can anybody help me this case? Thank youuuuu.

8901693--1218024--client conect.jpg

Can you ping the IP? Is the port open to incoming traffic on the server side (check firewall/routing)?

Yes, I can ping to that server. Port also open to incoming traffic too. In picture 2 I connect with terminal use IP and port it still ok. But when set IP, port to NetworkManager it can’t connect

I have the same problem too. I can ping the server but the network manager cannot.