Hello,
I have some problems.
For me this is wrong in the design of MKRGSM1400.
at the moment, developers advise to connect the battery. But this does not help, the MKRGSM1400 stops working and needs to be restarted.
We can not find a solution, as in this case, stop the loop and restart the MKRGSM1400 automatically.
For Arduino UNO we use #include <avr / wdt.h>, unfortunately it does not work in MKRGSM1400.