"Internet not availabe" Error on Samsung Galaxy A3 (2016) I have a Samsung Galaxy A3 (2016) model.

My mobile Wi-Fi keeps connecting and disconnecting; showing that the internet isn't available, this usually happens when my roommate connects to the same Wi-Fi network, as he starts using Wi-Fi, my mobile starts disconnecting, he has a Samsung Galaxy A7(2016) model.

When he resets the mobile Wi-Fi setting, my wifi works normally for some days then agin this problem starts.

So, my question is described above, and your solutions are welcome.
If the same thing doesn't occur on public networks (i.e. School or coffee shop networks) then I would imagine it's a problem with your router.