OK, that's the 2.4 GHz band. The biggest problem with 2.4 is the potential for interference. There are simply so many more devices on that band compared to 5 GHz. You might try changing it to either channel 1 or 11 and see if the connection improves. 1, 6 and 11 are the three best channels to use on 2.4 GHz. And if your router supports 5 GHz, that's the one you really want to use if possible. Using different SSIDs for each band allows you to be certain which band you use.
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