Yeah .. wierd title
So in my case: I am at location A and I am making a VPN to my local network what is at location B
I can access all my local servers and computers, but one !
“The One” is a server which has a dedicated openvpn connection to location C, when this is active my VPN from location A cannot access “The One” at location B. Only when the OpenVPN connection is terminated
Solution: add a static route on “The One”
check with: ip route show
and add the route like this: ip route add 10.10.10.0/24 via 10.1.1.1 dev eth0
where 10.10.10.0 is the VPN IP range what your local network is giving VPN users and via 10.1.1.1 is the IP of your gateway (router)
… easy peacy ..