Hello, @anurag1004

What happens when you execute ifconfig -a can you see the eth0 interface listed? If this one is not present then we will need to sort this out.

I know that sometimes some packages can be uninstalled somehow on reboot and there are cases where cloud-init is one of them. You can check if the package is present and currently installed on your droplet as well.

A similar issue was reported here as well: https://www.digitalocean.com/community/questions/no-internet-connection-after-droplet-reboot

You can check the answer posted from lukasea17033bb7e7ecf80fc21 and see the suggested steps if needed.

1. Create the /etc/udev/rules.d/70-persistent-net.rules file
2. Reboot tje server
3. Set the network interface using the information from the /etc/netplan/50-cloud-init.yaml file
4. Set the routing
5. Configure the dns resolver conf file (you can skip this if your resolv conf is still present, I know you’ve mentioned that you’ve already copied this from a working droplet)
6. You can run apt update and apt upgrade
7. Install cloud-init if it’s missing and ufw and landscape:

sudo apt install cloud-init

sudo apt install ufw

sudo apt install landscape-common

Also have you tried to power off the droplet and then start it again instead of just rebooting it? You can perform this action from the control panel.

Let me know how it goes.

Regards,
Alex