I have difficulties enabling letsencrypt automatic certificates

[he-ftv]

Hello,
I had to renew my HTTPS certificate. So far I have done it manually, but I would like to do it in the future with automatic configuration. Unfortunately I always get an error, see screenshot. The public IP address and DNS records are configured correctly and I checked our logs on the firewall and there is nothing blocked. Maybe there is still something to configure on Linux? Can you guys help me out? Thanks!

[evilaliv3]

@he-ftv: it seems that your firewall is currently blocking access on port 80.

The lesencrypt protocol is officially designed to work on port 80.

[he-ftv]

Hi, I don't even see traffic on port 80. All I see blocked are some weird random URL's (see screenshot). What exactly needs to be allowed for "Automatic configuration" ? Which URL's / Ports?