Assessment failed: Failed to communicate with the secure server

Hello dears, I introduce myself, My name is Martin. I am a programmer. I wanted to consult you regarding NGINX. I installed Ubuntu on a Digital Ocean server, it was working fine for me until I decided to add HTTPS with CERTBOT.

From there the website stopped working for me.

If I do a test with SSL Server Test: (Powered by Qualys SSL Labs) I receive the following message.


NGINX -T shows me that everything is OK.

nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful

I followed the guide Properly Enable HTTPS on Nginx with Let's Encrypt on Ubuntu and tried all kinds of configuration and I don’t know what else I can do to fix this problem.

I would greatly appreciate some guidance.