I tried to change the channels to 1,6 or 11 and am still having the same problem. the 2.4 GHz drops and the 5 GHz still working

I have a problem in the 2.4 ghz coverage. When I am nearly 10 meters indoors away from the router, the 2.4 ghz connection is so weak and sometimes it doesn't even connect. But at same time from the...