SIM7000A hanging with 'no data' sessions

Hello,

I have an IoT box that is powered by a solar panel and it connects every 15 minutes to post data.

Everything will work great for weeks then it will 'hang' and die.

It always hangs for 58 minutes and a couple of seconds, in this case, 58:06.

Can anyone tell me what to look for in the code, I am stumped.

Matt