Can't set up my astrobox


So, recently I wanted to set up an Astrobox for my printer. I had already a Raspberry 3 laying around and wanted to configure it. The only problem is that I don’t have a Wifi dongle. But after a bit of researching, I found out, that it can also be configured via ethernet. So I tried this method, but now I have a Problem with the Login. The Raspberry and the browser window requires a username and Password. So I tried out my current login methods, but they don’t work. After that, I tried logging in with the Raspberry password: Pi; raspberry, but I won’t even let me configure the settings. So I need some help. Could it be, that the Raspberry Pi just saved my settings from Raspbian and require them to work(I don’t know them anymore)? Thanks for your advice! :wink: