Uh-vpn is blocking proxifier

Hello, I created a private vpn using UH-VPN. The server is from Germany. When i want to start an app with the vpn connected, the app doesnt appear in the proxifier connections. When I turn off the vpn, the app works fine and its connected to the proxy. What could be the problem? Is the vpn blocking the connection to the proxy somehow? And if so, what could I do?
Thank you.