Azure VPN Gateway - Forced Tunneling

Hello, I have a Site-to-Site-VPN with an Azure VPN gateway where some local subnets on the UTM are configured. Now I have enabled forced tunneling on the Azure site, so that all traffic is send over...
HTTP ERROR 503 Service Unavailable

Greetings, After rebooting I got the following error I am waiting for help from those who have information on the subject
UTM 9 software as ProtonVPN client

This question hasn't been asked in 7 years. Has anyone gotten this to work. Essentially, I'd like Proton to be the parent proxy for the UTM. Thanks!