Unplug and RePlug Router

I have a GL.iNet Beryl (GL-MT1300) and I am using ethernet cable to get internet through WAN.

For the most part, everything has been working fine but every once in a while, I would have to unplug and replug the router to get connections again, especially when I noticed if I download a lot or running massive SQL queries.

Is there a reason behind this and what settings should I alter?