VPN won't let me RDP/Hyper-V remote manage anymore (WinRM), but only for Windows 11 23H2?

[SolidSonicTH]

So I'm not sure where I should be asking this because I don't exactly know what's causing this but based on my research I'm starting with the VPN.

My ASUS router has an OpenVPN server in it and normally I use it to remotely manage my Hyper-V server, which includes working remotely from a VM I host there.

However just last night I connected to it like I normally do but when I did I couldn't pass any WinRM (necessary for Hyper-V remote management) or RDP connections through but only for Windows 11 23H2 machines. If I RDP'd to my Windows 10 torrent VM I could make a connection and from there I could jumpbox through it to my 11 hosts. On the local LAN side I was able to do everything I wanted but coming through the VPN tunnel it seemed like my connection attempts weren't even being made (the Security event logs for those hosts showed no connection attempts being made from the VPN subnet).

I will say my network had been experiencing a hacking attempt in the recent past (which I only noticed by trying to address this problem) but those weren't related to the VPN (they were attacking a port I left open from an old network configuration that I was no longer using). I'm not sure that's connected but it's something (maybe my router is dynamically responding, I dunno).

Unfortunately at the moment the whole VPN config is broken because I tried reissuing the cert for the .ovpn file remotely and that locked me out of the whole network so I need to go back there and export a new .ovpn from inside the network. I also still have a couple Windows 11 22H2 machines I'd like to test to see if they're as stubborn about accepting connections.

EDIT: Seems some new twists manifested into this. I did the reverse of this (so connecting from the site that I was having trouble reaching into from outside back to the connection I started from) and was able to remote into a host on that side. However after I did that, disconnected, and then reconnected to the environment to do more testing I found that the same problem had suddenly manifested from this side as well (I can't remote into a system on that side through the VPN tunnel). So somewhere between when I connected the first time, dropped, then reconnected it lost the ability to establish connections to hosts via the VPN.

[SolidSonicTH]

I solved the issue. I was being a dunce.

Both subnets that I'm connecting to and from are in the same local range so I was getting IP address conflicts from my local subnet to the remote site and vice-versa. I thought OpenVPN auto-negotiated this but I suppose maybe I was a little too presumptuous (mostly since the RDP connection via VPN doesn't drop when I use that host to connect back to a VPN).

Unfortunately that means I have the headache of needing to re-address one of my sites so the reserved DHCP IPs there don't conflict with the fully dynamic IPs at the other end, which could break a lot of services if I was using IP addresses to point to things...