You will also get this error while trying to connect from the device Settings, please connect\disconnect Hotspot Shield from the app's dashboard as it will not allow you to control it from Settings.
If you continue experiencing the error:
- Reinstall the app's profile, it should fix the issue;
- From iOS settings > General > Profile
- Select Hotspot Shield Profile
- Delete Hotspot Shield Profile
If the steps above don't work and you are located in any of the following countries: Pakistan, Iran, Oman, Qatar, China, UAE, Saudi Arabia
- Click "Contact Support"
- Provide a description of the issue and a screenshot (If possible)