[Network] Cannot Connect to my Server After Build

I have create 2 projects (Client & Server)
when I run Server “by Unity” in my laptop.
then I run Client “by Unity or .exe” in other laptop. They can connect to my Server.

but when I run Server “by .exe”. They cannot connect.
???

!@#!^%#^!%#
I got Answer!!!
I should build exe into another directory (not in project). . . . . .