Settings> Connections> Mobile networks> Enable Data roaming.

Then go to Access point names> Add> Edit access point :

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NAME : HOT

APN: net.hotm

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Choose save in the option menu then check HOT on the screen. 

You will see the signal H / H + / 4G / 4G + / LTE at the top right of your screen

 

> If the internet does not work immediately, restart your phone and check again.