Help Center

If your phone displays a SIM Card error message, do a couple of quick checks.
Firstly, ensure that you have inserted the Tello GSM SIM into a compatible device - use our device checker to confirm this.
Secondly, ensure that your phone is unlocked. Contact the previous phone carrier (or phone seller) to confirm this.

Once you have confirmed the above, follow these steps:

• Turn your phone off.
• Remove the SIM Card.
• Make sure the SIM Card isn’t damaged or you’ll need a replacement.
• Insert the SIM Card back into your phone.
• Turn your phone back on, follow any on-screen steps provided and your phone should start to automatically activate the Tello service.

Here’s a quick list of some of the most common SIM Card errors you may run into:

• "sim not supported"
• "network lock,"
• "network unlock pin,"
• "unsupported sim"
• "SIM Lock"
• "SIM Invalid"
• "Network Lock"
• "SIM Not Supported"

If you receive any of these error messages, your previous carrier may have enabled a lock or restriction to your phone and you will have to reach out to them to remove this lock.