Found a similar issue here but involved Hyper-V VM's and Host.
In my case i sense something bizarre.
I've established a connection using only PPTP built-in windows connection between two points. Everything seems to be working, from the client i can access the router and other machines of the remote network just fine, problem is i can't access the very same computer that is providing me with the VPN tunnel connection.
Wait for it, i'll make it worse: i can't ping the windows machine where i've set the VPN server, can't access its own shared folder either, but when i open MSSQL Studio i can connect to its database! Basically i can't even ping the address 192.168.1.1 but when i try to connect from studio using 192.168.1.1\sqlinstance it connects no problem.
I appreciate any help you can provide, i don't know what i'm missing tbh...?
TLDR: windows -> windows PPTP, can access network all around but the very single windows pc that's providing me the access tunnel.