Dear Sir,
Please confirm whether you use the private network SIM card? If yes, whether you use the right APN, username, password? Whether you have change another SIM card to have a try?
Form the log you provided, we can not confirm your issue, please use command ifconfig wwp0s20u4u4i4 to check whether get IP address. Thanks!
By the way, where are you come from, EC20 module is design for China domestic marketing, if you are oversea marketing, you must use EC25 module, not EC20. Thanks!