If its the gui, you can use the forgot password (cancel or get the password wrong enough). If you set it up, it'll then ask for serial number and the answers to questions you setup. If you didn't setup the recovery answers then you might be needing to reset the device back to factory to get into it.
If you've forgotten the wifi password, just log into the router either from a device already connected to wifi or hardwire into the router. From there you can go to routerlogin.net, log into the device, and go to the settings section to find wifi ssid and password.
Current setup: CAX80->Trendnet TEG-S380->GS716T-> RBK752->pi-hole 1.4gig download/50mbps upload We’re members of the public helping out on our own time.
If you've forgotten the wifi password, just log into the router either from a device already connected to wifi or hardwire into the router. From there you can go to routerlogin.net, log into the device, and go to the settings section to find wifi ssid and password.
As well as the sound advice from @plemans, if it is more convenient, you can use an app for whatever mobile devices you have, Android or iThing, to recover the wifi password for the R8000.
Perhaps that is what you wanted. After all you have posted in the apps section rather than the one for the R8000.
