No access to Internet nor localhost when connected to OpenVPN vpn on Ubuntu 20

On Ubuntu 20 I have received and client.ovpn file and I tried connecting using the following command

sudo openvpn --config ~/Download/client.ovpn

but that didn’t work because I couldn’t connect to the website which was behind the VPN. Actually, I couldn’t resolve the DNS of that protected server.

Then I went to Activities -> Network -> Under VPN .> Import from file. I imported the client.ovpn file and connected to VPN successfully and I can access the protected website I was supposed to. But now I cannot access anything else on the Internet not my server on localhost.

I went through the Internet looking for solution but I just cannot get it to work. And to make things worse, I’m not good with networking setup and VPNs.

Here is the ip route before connecting to VPN and after if that helps.

Before connecting to VPN

➜  ~ ip route                          
default via 192.168.100.1 dev wlp0s20f3 proto dhcp metric 600 
169.254.0.0/16 dev wlp0s20f3 scope link metric 1000 
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown 
172.19.0.0/16 dev br-9d2526679794 proto kernel scope link src 172.19.0.1 linkdown 
192.168.100.0/24 dev wlp0s20f3 proto kernel scope link src 192.168.100.4 metric 600 

After connecting to VPN

➜  ~ ip route
default via 10.200.136.1 dev tun1 proto static metric 50 
default via 192.168.100.1 dev wlp0s20f3 proto dhcp metric 600 
10.0.0.0/8 via 10.200.136.1 dev tun1 proto static metric 50 
10.200.136.0/21 dev tun1 proto kernel scope link src 10.200.142.215 metric 50 
35.161.223.96 via 192.168.100.1 dev wlp0s20f3 proto static metric 600 
140.100.0.0/23 via 10.200.136.1 dev tun1 proto static metric 50 
169.254.0.0/16 dev wlp0s20f3 scope link metric 1000 
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown 
172.19.0.0/16 dev br-9d2526679794 proto kernel scope link src 172.19.0.1 linkdown 
192.168.100.0/24 dev wlp0s20f3 proto kernel scope link src 192.168.100.4 metric 600 
192.168.100.1 dev wlp0s20f3 proto static scope link metric 600