Troubleshooting connection issues can be challenging.
If your connection worked before taking an action then, before anything else, try to undo that action, to restore the connection.
If your connection is still not working, then the problem can be one of the following:
1. Your router/modem - Check it's Admin panel for any firewall and if it's on, try to disable it.
2. Your device internet connection settings - You can reset your network stack as shown in this guide
3. Your firewall - Try to disable the firewall temporarily.
4. Your VPN - Try to uninstall the application temporarily.