help cascading routers F34

Monday, 21 February 2022

for the last several yrs, i've used att's pace 5238ac cascaded to my
nighthawk R8000.

pace wifi off, all wifi from nighthawk.

recently got a bandwidth update (internet-24 to internet-50)
and att swapped the pace for arris bgw210-700

now i cant get the cascaded setup to work.

i've been googling all week w/no joy...

any wisdom out there??