I have your Sixfab 3G,4G/LTE shield and EC25 module. I followed your tutorial https://sixfab.com/gps-tracker-with-3g-4glte-shield/ and I have problem. When I write down AT+QGPS=1 in minicom I get “+CME error: 504”. Do you know why? Besides I don’t see what I typing in minicom (like typing of a password).