I've had this monstrosity for a couple of years and nothing but problems

[NP123]

I've had this monstrosity for a couple of years and nothing but problems (am in Canada, so only really use it in the summer to extend range to my patio). Eventually had to connect to modem via Ethernet which worked for a while and now even that is not working. Have power-cycled, factory reset and done everything countless times and still run into the same issue: I appear to be connected , with full strength, but NO INTERNET CONNECTION!  (All lights are white and nothing flashing, but no access)

I have a crappy old DC link extender that works better but only single band so not ideal - especially since I dropped $200 + $35 on Ethernet cable to make this thing work! Can someone help? And please, something other than everything I have already tried.

[FURRYe38]

Would be helpful to know what brand host router and model # the EX7700 is connected too. 

What FW is currently loaded?

What distance the EX7700 is from the host router.

What channels are you using on the host router.

[NP123]

SagemcomFAST5566

Latest firmware

20ft (hardwired ethernet)

What do you mean by channel?