Thanks for your posts Beth and Sara. The more I look into this, the more I believe that Sara is right; I just don’t have 2G service where I live. I found an old Raven 2G modem, plugged it in and it couldn’t connect either. Even knowing that, I tried to run the script that Beth suggested but couldn’t get it to compile:
error: ‘class Adafruit_ADS1115’ has no member named ‘readADC_SingleEnded_V’,
adcVoltage = ads.readADC_SingleEnded_V(_dataPin);
I think I need to learn PlatformIO and see if it finds better libraries. In the meantime, I’m going to start looking at 3G boards.