this is actually the second try after starting everything to the factory defaults. The PIN that I entered in the previous screenshots is the one we got for the sim card, so it should be correct. Does it make a difference, if the simcard is pre-paid or purchased with a contract for unlimited mobile data?
I´ve tried already with all APNs available in Auto Mode. When I entered the SIM card in my phone, I was able to call and use internet, so the sim card must be active.