Sudden ACME error


I just upgraded to 1.7.18 and all of a sudden I get ssl certificates errors:

[INFO] [,,,,] acme: Obtaining bundled SAN certificate"
[INFO] [] AuthURL:"
[INFO] [] acme: use tls-alpn-01 solver"
[INFO] [] acme: Trying to solve TLS-ALPN-01"
[INFO] Unable to deactivate the authorization:"
 acme: Error -> One or more domains had a problem: url: \n[] acme: error: 400 :: urn:ietf:params:acme:error:connection :: Timeout during connect (likely firewall problem),

But all containers are up, and are accessible via https.
I can open them but I get the Traefik dev ssl certificate.
The entrypoints are served only via IPV4.

This is my traefik.toml:

defaultEntryPoints = ["http", "https"]

       address = ":80"
        entryPoint = "https"
       address = ":443"
       address = ":8080"

  caServer = ""
      main = ""
      sans = ["", "", "", ""]

Is there any configuration setting that changed between the two versions, 1.7.14 and 1.17.18?
And I should set it now, in order to make acme work again?

So, it had nothing to do with Let's Encrypt or Traefik.
Some firewall rules were added without my knowledge, that prevented Let's Encrypt from connecting to port 443.. :frowning: