Use Free SSL from Let’s Encrypt

Install in any server:

sudo apt  install certbot

Then run this command:

certbot -d bot.arifdev.com --manual --preferred-challenges dns certonly

Then add the certificate to Nginx/Apache:

# Nginx example
listen 443;
ssl on;
ssl_certificate /etc/letsencrypt/live/bot.arifdev.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/bot.arifdev.com/privkey.pem;