Hello,
For 2 years, I have a problem with the Arduino GSM Shield.
It works very well about 7 or 12 days and after this delay, the Arduino Card + Arduino Shield store the SMS which it receives but it refuses to send any messages in my program.
At the beginning, I thought it was the little RAM of Arduino UNO => it wasn't
After, I upload the bootloader to Optiboot => No change
After, I used a Arduino Mega 2560 => No change
I changed lots of things in my program and I used lots of "flush" command => No change.
If you have an idea to help me meanwhile I reset the system each week.
Thanks
Thierry