What if port 80 is inaccessible and stopping TLS-SNI-01 with Certbot

[JuergenAuer]

PS:

A check on https://www.yougetsignal.com shows that port 80 is open … .

What check did you used?

Using

Open Port Check Tool - Test Port Forwarding on Your Router

with your domain name:

Port 80 is closed on blucap.no-ip.org