Can access client through access server, but the client cannot connect to external hosts

I would like to access my client via SSH through my access server. Therefore, I forward port 667 on my access server’s WAN IP to port 22 of my client’s VPN IP. However, the connection times out, with the packets not arriving on the client’s end. If I enable routing on the access server and pass 0.0.0.0/0 to Specify the private subnets to which all clients should be given access (one per line):, I can access my client just fine. However, now my client cannot access external hosts (e.g. ping 8.8.8.8 fails). What is the correct way allow access to my client while maintaining its connectivity to the internet?