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It have only 3 option in the app: public server, favorite servers and LAN server

what area code is your server?

sorry but im just confuse when it comes to this :)

In one of the 3 options there may be the possibility to add a new server, as it is not a public server.
If you use the app you have to connect with a server first, and this is the moment when you should have the choice to create a new one.

sorry Im just so bad at this, and I dont have anyone around me to ask, so if you have skype, my username is maianh.nguyen4