ok I have done this with my AR-750 Number 2:

I see him on the Smarthone as WLAN GL-AR750-110-5G und get the IP 192.168.8.110 . But in the Browser I cannot reach him under 192.168.8.1

why??

update:

I reach him under 192.168.8.1 on my Tablet .
The admin-password is the old !
I connect him via WAN-port to my Fritzbox
sucessful hi gets the lokap IP 192.168.9.16
Under "Aktualisierung I see “aktuelle Version 3.211” and
“letzte Aktualisierung unavailable”

here in the Fritzbox AR-750 is seen under 192.168.9.16, but the WebInterface doesn’t respond.

update 2:

now are both AR-750 #1 and #2 seen in Fritzbox, but no WebInterface

this is a look to GL-Cloud:

as you see was #2 yesterday for a short time online in Cloud

and here I have the SystemStatus of #2:






So I can reach AR-750 via Luci only on the Tablet Samsung 825, not in Samsung S20, not on PC-Webbrowser (Fritzbox)