I cannot download updates via vpn

[JohannesBe]

I have a always on vpn connection using openvpn.

When I turn on the always on feature, I consistently get the following error message:

Note that I can surf the web just fine.

I tried checking the connection settings of my updater app, but they seem fine:

Any ideas what is going wrong or how I can fix this?

Thanks in advance.

[JohannesBe]

I also noticed it stops checking for updates as long as I have my VPN running. Therefore I regularily have to specifically un-block my connections in my vpn settings in order for my lineageOS to even find new updates.

[JohannesBe]

If you need more debugging information, I'm happy to provide this, but I will need some assistance with getting the relevant information.