Miracles in the network, or why does the laptop quarrel with d-link?

Question

linux

On a laptop - Ubuntu
Router: DIR-615 (I connect via wifi).
The connection is stable, the connection is good (laptop and router on the same table).
But sometimes such a moment comes that the laptop stops connecting to the router (the wifi icon on the laptop blinks for a long time).
At the same time, the phone and the stationary computer connect to wifi quietly, and the laptop calmly connects to other routers.
The problem is solved only by rebooting both devices.

Answer 1

Is the channel selected specific, or is it set to auto? It is advisable to choose a certain