ssl cert with lets encrypt?

[kimusan]

Hi,
I was wondering if you have an idea for how to get ssl cert via Lets Encrypt so it works with guacamole in CIAB?

I can get certbot to get a cert on the main host machine, but the site still serves the self-signed one from the nginx docker container.
If I run certbot on the nginx container I tells me that it cannot get the cert for the domain

Certbot failed to authenticate some domains (authenticator: nginx). The Certificate Authority reported these problems:
  Domain: xxx.yyy
  Type:   connection
  Detail: x5x.x5x.x8x.x4x: Fetching http://sxxx.yyy/.well-known/acme-challenge/VQnEZc9e2N9GsPOVeNiffI-g6_ezxnjM8nACE5PpQAY: Connection refused

(the domain etc is anonymized but I use the actual domain that the system is accessible via.)

Any ideas?