Help Center

If you have activated your SIM in your Tello account but the service still does not work on your device, there are a few steps you need to follow in order to check the activation completed correctly.

1. SIM /eSIM Check
If you ordered a physical SIM, Power OFF your phone, remove the SIM and check it is inserted correctly. For this we suggest checking the steps for your Android or IOS device model online as it can have some variations. Alternatively, you can also check this guide on our blog.

If you ordered an eSIM simply restart your phone and check the eSIM is correctly configured under settings.

• Android: Settings > Connections/ Network & Internet > SIM Manager/ SIMs > check the Tello eSIM is ON.
• IOS: Settings > Cellular > Under the SIMs section, check the Tello eSIM is ON.

Additionally each type of device will also offer different settings for Dual SIM preferences. In case you have more than one line in the same device, make sure the correct SIM is selected for calls and data services.
For more detailed steps on Dual SIM configuration we advise consulting the respective manufacturers instructions.

2. SIM Error "Invalid SIM" or similar.
If after inserting the SIM card or installing the eSIM, your device displays a "Invalid SIM", " Network Unlock PIN" or similar notifications; this indicates your phone is carrier locked to another service provider.
On iPhones, you can also check this by going to Settings> General > About > Carrier Lock. SIM Locked means the device is carrier locked.
To unlock the device or verify the lock status you will need to contact the provider of the phone.

3. Software Update check
Check that your device has the latest software version installed.

• Android: Tap Settings > System> Software Update.
• IOS: Tap Settings > General > Software Update.

Download and install any updates available, restart your device and test the service.

4. Network Technology check
Ensure that VoLTE is enabled.

Android:

• Go to Setttings> Connections/Network & Internet > Mobile Networks >
• If you have an option for VoLTE, make sure its ON (In some models this optpion can also be named: Enhanced 4G, HD Calls or similar)

IOS:

• Tap Settings > General > Cellular (or Mobile Data) > Ensure the Cellular Data (or Mobile Data) switch is in the "ON" position.
• Tap Cellular Data (or Mobile Data) Options > Tap Voice & Data.
• Ensure LTE is selected (has a checkmark). If not, tap.
• Ensure the VoLTE slider is in the "ON" position.

*These instructions are for the newest iOS versions (iOS 14 or above). On older versions of iOS, the process to turn on VoLTE will be very similar.

5. APN check
Check that your APN settings installed correctly:

• Android (dropdown or link)
• Tap on Settings > Connecctions/ Network & Internet > Mobile Network > Access Point Names
• Check the avaiblae APN settings in your device, by default might be (fast.t-mobile.com)
• If you dont have the default APN , then tap on the 3 dot menu > Reset to Default
• After this, the default option might show and you need to select it.
• Alternatively, you can ADD a new APN with the next details:
  • *Name: APN
  • *APN: wholesale
  • *MMSC: http://wholesale.mmsmvno.com/mms/wapenc
  • *Proxy: (leave blank)
  • *Port: 8080
  • *Username & Password: (leave blank)
  • *Server: (leave blank)
  • *MMS Proxy: (leave blank)
  • *MMS Port: (leave blank)
  • *MNC: 240
  • *Authentication Type: (leave blank)
  • *APN Type: default,supl,mms
  • *Protocol: IPv4
  • *MCC: 310
• Save the setting, select it and reboot your device to test the service.

• iOS (dropdown or link)
• Tap Settings > Cellular or Mobile Data > Cellular Data Network / Mobile Data Network:
• By default iPhones and other IOS devices will show the next APN settings when using the Tello network:
• Mobile Data
• APN: wholesale
• MMS
• APN: service
• MMSC: http://wholesale.mmsmvno.com/mms/wapenc
• Personal Hotspot
• APN: wholesale
• Leave everything else blank.
• If any of the fields is empty or incomplete, scroll down to the last opton and tap on "Reset Settings" to reset the APNs to default.
• Alternatively if the APNs so not set automatically after the reset, enter the information provided above.
• Finally reboot your device and test the service.

6. Reset your Network Settings
If none of the previous steps solved the issue, please reset the network settings on your device. Note, This also resets Wi-Fi networks and passwords, cellular settings, and VPN and APN settings that you've used before so ensure you test the steps above first, before trying this step.

Android

• Go to Settings > General Management or System > Reset options > Reset Network Settings ( Reset Mobile, Wi-Fi and Bluetooth)
• Reboot your device and test the service.

iOS

• Tap Settings > General > Reset or Transfer > > Reset > Reset Network Settings.
• Enter your passcode and wait for the device to restart on its own.
• Test the service

If the service is still not working properly after doing these checks and trying these steps then email us with the following information:

• The exact problem (calling, messaging, data etc)
• The IMEI of the device
• The phone number of the device
• The troubleshooting steps you have tried
• Any error messages (if any) that appear on your phone
• The exact address where you are having issues.