There is no direct release-upgrade path that is supported.
The supported method is to release-upgrade from 16.04 to 18.04, then release-upgrade again from 18.04 to 20.04. Stop and troubleshoot any problems you encounter before continuing.
A backup or VM snapshot or VM clone before beginning is wise.
sudo apt update
sudo apt upgrade // Prepare the ...
Further to Emoji's answer, I would recommend taking a disk image of the virtual machine before proceeding with the upgrade. How you take the disk image will depend on what virtual machine hypervisor software you are using. You can find instructions for VMware here.
Once you have a backup for safety, to perform the upgrade is relatively straightforward using ...
I downloaded and installed the latest VMWare Player from VMWare and now everything works. I had been running 15.5.1, now I am on 15.5.6. You get a .bundle file - I just chmod +x reallylongfilename it and sudo ./reallylongfilename and Bob's your uncle.
If updating VMWare Player isn't an option, you might wish to look at this thread: https://communities.vmware....
You have specified a gateway that you don't have a route to. 18.104.22.168 is not in the network 22.214.171.124/30, therefore it is unreachable and you have not told your system where to send Internet traffic.
You have also specified a redundant route entry for the network which is already defined as local due to your addresses.
From the tutorial you linked,...
Doesn't command a specific version in the instructions but it makes note of one (unless the link it provides passively implies which one to use).
Provides step by step instructions.