BPI-R3 4G/LTE Modem

Hey guys, I bought a 4G modem, installed the whole thing and it is also recognized / works properly. however, I do not get a connection established, does anyone have an idea what this could be?

Link to PCI-E 4G LTE Modul: https://www.amazon.de/dp/B07WPYPZMF?psc=1&ref=ppx_yo2ov_dt_b_product_details

There a fair bit more diagnostic information you coudl provide… like what kind of error message does it provide?