Verify that you have an Internet connection when Hotspot Shield is not running.
Now, please follow these troubleshooting steps:
1. Turn ON Hotspot Shield and wait a few moments for it to connect
2. Try reinstalling the profile from within your app using the following steps provided in this article.
3. Once Hotspot Shield is ON and connected, turn Airplane mode ON then OFF
4. Try to connect again
If the steps above didn't solve the issue, please disconnect Hotspot Shield on other devices that have it active on the same WiFi network and try to connect Hotspot Shield on your iOS device only. Some WiFi networks don’t allow traffic from more than one VPN on one device, therefore, if that’s the case, you will only be able to connect Hotspot Shield on your iOS device when it’s turned off on the other devices connected to the same network.