# SIM900 stopped working

**URL:** <https://forum.arduino.cc/t/sim900-stopped-working/493084>\
**Category:** GSM Shield\
**Created:** [November 24, 2017, 1:04am UTC](https://forum.arduino.cc/t/sim900-stopped-working/493084 "2017-11-24T01:04:03Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![TomasCanales](https://avatars.discourse-cdn.com/v4/letter/t/35a633/32.png) [@TomasCanales](https://forum.arduino.cc/u/TomasCanales)\
**Post date:** [November 24, 2017, 1:04am UTC](https://forum.arduino.cc/t/sim900-stopped-working/493084/1 "2017-11-24T01:04:03Z")

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Hi, I was using the SIM900 shield to send an SMS, everything worked perfect. When I tried it again at 15 minutes it did not work anymore.

```cpp
#include <SoftwareSerial.h>
SoftwareSerial SIM900(7, 8);

void setup() {
  SIM900.begin(19200);
  delay(25000);
  Serial.begin(19200);
  Serial.println("Conectado");
}

void loop() {
  sendSMS();
  delay(100);
  SIM900.println();
  delay(30000);
  while(1);
}

void sendSMS() {
  SIM900.print("AT+CMGF=1\r");
  delay(100);
  SIM900.println("AT+CMGS=\"xxxxxxxxxxxx\"");
  delay(100);
  SIM900.println("Mensaje enviado desde Arduino con GSM/GPRS Shield SIM900");
  delay(100);
  SIM900.println((char)26);
  delay(100);
  SIM900.println();
  delay(5000);
  Serial.println("Mensaje enviado con exito!");
}

```

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<div class="post-metadata">

**Author:** ![dannable](https://avatars.discourse-cdn.com/v4/letter/d/76d3ee/32.png) [@dannable](https://forum.arduino.cc/u/dannable)\
**Post date:** [November 24, 2017, 7:40am UTC](https://forum.arduino.cc/t/sim900-stopped-working/493084/2 "2017-11-24T07:40:08Z")

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Two suggestions:

1. Check your connections, make sure none have come loose.
2. Try running SoftwareSerial at 9600.

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<div class="post-metadata">

**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [May 6, 2021, 5:49pm UTC](https://forum.arduino.cc/t/sim900-stopped-working/493084/3 "2021-05-06T17:49:01Z")

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