Registration information not correct

Hi, I just bought a smart radiator thermostat and I need to set up the internet bridge. Every time I try to register the serial number on the bridge, I get the following error: "the registration information you have entered is not correct. Please try again". I mush have tried 50 times now, and I have also tried to enter the serial number manually 3 times, but it still tells me that it"s incorrect. Can you please help me?