How to install SSL on DigitalOcean Docker Droplet without domain name?

I have a running docker droplet on DigitalOcean but this droplet running on http and I want to run it on https.

I don’t want to purchase any domain name. Actually I don’t need a domain name, ip address is enough.

Certbot and Letsencrypt are not allowing creating SSL certificate on bare IP address.

Is there any solution for this problem?

How can I do that?

Thank you for your collaborations.

Source: StackOverflow