Arduino UNO rebooting alone

Question

Good afternoon, I have an Arduino UNO, and a Shield GSM ICOMSAT 1.1 here, was working normally with both, receiving and sending Smss, but when I added a Shield SD Card to generate a Datalogger the Arduino is rebooting alone. So I only tested the SD Card, and it worked perfectly. But the Shield GSM and the Shield SD Card don’t work together. Someone knows why?

Image of the Serial Monitor:

Code Used: Github

Funny that if I comment on that part of the code:

myFile = SD.open("dados.txt", FILE_WRITE);
if (myFile){                                     
  Serial.print("Escrevendo em arquivo...");     //Escreve no arquivo
  myFile.println("hello SD Card Shield!");      //Teste de escrita

  myFile.close();                               //Fecha o arquivo
  Serial.println("Escrita finalizada");         //Informa escrita finalizada
}else{
  Serial.println("Erro ao abrir arquivo");      //Informa que há algum erro
}

Hence the engine does not restart, however, I cannot write the data to the file. txt.