Kindle Paperwhite 7th Gen says "unable to connect"

Kindle model no DP75SDI

Hi guys! So I recently purchased a kindle (which I believe is the Paperwhite 7th gen).

It's been factory reset, and whenever we try to register an account or log in to an account, it says "unable to connect" despite the fact that we have successfully connected to the wifi router at home. (It says connected in the settings)

We have tried everything and nothing is helping!
Performed a hard reset,
Factory reset again,
Forgotten and re-connected to the wifi,
Manually updated the kindle via laptop,
Connected to a 2.4 GHz network (via mobile hotspot),
Reset the date and time

Does anyone have any ideas what we could do? Honestly at this point I'm about ready to throw it in the bin. Any help is greatly appreciated!!!