Zyxel NR7101

I'm having two issues with my router.

1. I don't have the original PW for wifi to use after factory reset. Any way to retrieve this ?
I've tried scanning the QR code on the lable with serial number on located on the unit backside with Zyxel Air app, but only get the message "Sorry, QR code is invalid"

2. Connecting directly with ethernet cable via POe power to PC. I get the diagnostic message that " Local connection don't have valid IP-config"

So at the moment I'm pretty stuck here.
Else for info, the SIM inserted is valid with no PIN, but LED keep blinking green or orange when wifi is enabled. No steady light.