why my 3CX phone can't connect to my server?

[bond_shu]

I configured a 3CX phone system on computer A as server, then install 3CX phone on the same computer. The client can connect to server and make call.
Then I install the client on another computer B, and configure account there, but the client on computer B can't connect to server.
Note: both A and B are in the same domain, and all 3CX phone system service are allowed by anti virus system.
why the client on B can't connect to server, and A could?
Anyone could help?

 

[filipe]

logs?

 

[davidbenwell]

Do you have a firewall on server A?