VPN only works to access the configuration gui

I've been trying to establish a VPN to access my data remotely.

However, I can't seem to get it to work. My phone and computer can connect to my VPN (OpenVPN plugin) but they cannot access the internet.

The only thing that works is accessing the control panel from the server using my public IP.

Does anyone know what I did wrong?

If additional info is needed, I will post it as fast as possible

Kind regards

Update:

I'm also able to access my server using the VPN but I'm just not able to access the public internet using it.