July 2021 on Mastodon. I can’t remember why, probably because it sounded like an interesting concept. Later I tried to use lemmy a few months before the reddit stuff started, but there was not enough content, so I forgot about it until a few months ago.
I have a Wireguard VPN to my home network and there it works exactly like you tried it. Connect to VPN, then use the internal IP to connect to the service. Maybe there are settings in the server or client that prevent that. For example, you can set specific IP ranges to not be routed through the VPN (so you can access a local service in Network A even though you are connected to VPN B).
I’m no network expert, but maybe some additional information about your setup can help other user help you better.
You will probably have transformed into a monstrous vermin when you awake from uneasy dreams tomorrow morning.