@psychobunny: Thanks for your supporting.
After admin help me, Forum Base URL is changed to http://khoapham.nodebb.com
But domain I want is: http://forum.khoapham.vn
Please help me.
So, I've configue forum.khoapham.vn to 126.96.36.199 (I follow SASS plugin).
Just wondering that did I wrong?
And what to do next to use my own domain?