Please, try to do the following:
1. Go to Home Screen -> Settings -> VPN -> Tap (i) next to the VPN Unlimited profile -> Tap Delete VPN configuration.
2. Delete the VPN Unlimited app and reboot your device, it is required.
3. After you have rebooted your device install the VPN Unlimited app from the App Store again: https://apps.apple.com/app/apple-store/id694633015
4. Then open the VPN Unlimited app, choose any server by tapping on a country flag and the VPN Unlimited app will install a new profile (configuration).
This manual may be helpful: https://www.vpnunlimited.com/help/manuals/ios
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