Issue: I'm on an Android device and I cannot connect to Hotspot Shield. My carrier is T-Mobile.
How To Troubleshoot Connection Issues on Android with T-Mobile
If you are receiving "EC_3003" while trying to connect on your Android or iPhone, it is because IPv6 is not yet supported by T-Mobile.
(Note: These instructions do not work on iOS devices.)
As a temporary workaround you will need to complete the following steps:
1. Open "Settings"
2. Tap "More" 3. Tap "Cellular Networks"
4. Tap "Access Point Names" 5. Pick your "APN" and tap on it
6. Tap on "APN Protocol" 7. Select "IPv4"
8. Exit "Settings"
For More Information, Please See:
Troubleshoot Android Connection Issues