Enable IP Forwarding in Linux. This is required when setting up wireguard or using ssh tunnels

sudo sysctl -w net.ipv4.ip_forward=1

net.ipv4.ip_forward = 1

OR

echo 1 > /proc/sys/net/ipv4/ip_forward

Make it Permanent

sudo nano /etc/sysctl.conf
net.ipv4.ip_forward = 1