📘 What does a +CMS ERROR mean?

📶 What is a +CMS ERROR?

A +CMS ERROR is a standardized error message used in mobile communications.
It indicates an issue related to the mobile network , the SIM card , or the cellular modem – typically in the context of SMS sending or receiving.

These errors help identify the root cause of failed actions.

📋 Overview of Common +CMS ERROR Codes

🛠️ Troubleshooting Tips

❗ Example:+CMS ERROR: 500 – Unknown Error

This is a generic error with several possible causes, such as:

• ❌ Multi-SIM or multi-provider SIM card in use

• 🔒 SIM card not activated or blocked

• 📵 SIM not SMS-enabled (e.g. data-only plan)

• 💰 No remaining balance (for prepaid cards)

• 🔐 SIM PIN not removed

• ✉️ Incorrect or missing SMSC address

🔍 Tip: Check the SMSC Address

The SMSC (Short Message Service Center) address is critical for SMS transmission.
If it's missing or incorrect, SMS sending will fail.

✅ How to Check the SMSC Address:

📱 On a mobile phone:

• Look into your SMS/message settings

• Or contact your mobile service provider

🖥️ On the gateway (only accessible during a remote session by brevis.one support) :

• Must be queried directly via system console (e.g. using minicom or screen)

• Command:
  AT+CSCA?
  (after connecting to the modem port)

📌 Summary

• +CMS ERRORs provide targeted information about mobile-related issues

• Most errors are linked to the SIM card , network availability , or misconfiguration

• Code 500 is non-specific → it requires a systematic check of:

  • SIM card status

  • PIN lock

  • Network availability

  • SMSC configuration