I was trying to renew my SSL certificate on my droplet by following this guide: https://certbot.eff.org/lets-encrypt/ubuntubionic-nginx
But for some reason I kept getting 28: No space left on device when I run apt-get...
I would recommend starting with the following:
First check how much space you have available and which partition is filling up with the following command:
The output would look something like this: