EM7565 activation at xubuntu 18.04

I use Lenovo X1 Carbon 6th newest Bios 1.34. The installed Fibocom 850GL works under Windows but not with Linux. So I replaced the card with EM7565. When I set up a mobile broadband connection with ModemManager, I can choose the device “cdc-wdm0”. But I cannot establish a connection, the sytem show me “mobile broadband not activated” and I do not know how I can activate it now.
Please get to know that I am a linux newbie.

Thank you for any help!