Internet is fine but an app does not connect to its server

[Android Central Question]

I have a samsung j7 2016 and a nokia x2 android phone.
the j7 got android 7.0 and the nokia got android 4.1

the problem is this:
the internet is shared over wifi in my home.
both phones connected to internet and has full access no problem.

BUT the problem is a single app called Line Webtoon does not connect to its server on J7 But it works totaly fine on the Nokia.

I tried these:
1- clearing app's cache
2- clearing app's data
3- removing and reinstalling the app
4- reset network settings
5- I even factory reseted my new Phone (the J7)!!

I can make it work with a proxy or vpn on J7 but its working on the nokia without the proxy so its not some regional issue. it should be my J7 right?

I dont have other non-samsung phones around but my bro told me he cant connect either (he also got an samsung A7 2018).

I dont know if its related to samsung or not but i can tell it should be a problem in setting or something? can anyone help me fix it so I dont need a proxy?

 

[Rukbat]

Contact the developer at dl_linewebtoon@webtoonscorp.com. They can see what it's doing and why. You can't and we can't.