This is how VPN works, you tell the system to use the vpn tunnel to route all traffic to, outside that IP range, it should not work.
So the software should enable you to make an exception for local ip addresses, next to the outside IP.
If you are on a commercial vpn provider like NordVPN, it should work via settings menu (it works here).
In case you setup a VPN eg with your company network, it is sometimes possible to setup a split tunnel if the software allows you to do so. You can find data on internet if you google for e.g. "Split VPN Tunnel"
But I agree with Rusty that more info is needed if the above is not sufficient.