I reset and swap both the units, the unit that was initially the main is now the 2nd unit while the unit that was initially the 2nd unit is now the main unit. It works for me now

I am using Deco M4 (2 packs). 1st main Deco is at the first floor connected wired to the modem, 2nd Deco unit is connected wired from the 1st Deco unit at the ground floor. I am experiencing...