Hi @Anonymous User
I doubt two sticks would fail at the same time, where it sounds like either an internet or Router conflict.
If it was me the first thing i would try is to disconnect the power to both the sticks and your router for about a minute, then restart your Router first (give it say 5 minutes to settle down) then restart both your sticks.
Should you still be getting no joy, then maybe see if anything in this linked below trouble shooting guide makes any difference.
https://help.nowtv.com/article/troubleshooting-now-tv-box-stick
One final thing you could try if none of the above resolves it, is to power down your Router for about 30 minutes.
Otherwise see if NowTV live chat can assist and help you further.
Goodluck.