Haproxy + letsenrypt. hostname directs to another port

  • Sorry for the probably bad headline.

    I have a container (small server) with MySQL installed. Reachable at
    I have set it up so lets encrypt fetches a wildcard cert *.contoso.com, added the name mysql.contoso.com in frontend/backend as ACL (or whatever its called). And also in the DNS resolver.

    It works, so when I go to mysql.contoso.com the page pops up.
    However, on that page, there are 3 buttons (webmin, shell and adminer). They point to different ports: 12320, 12321 and 12322 withe the same IP of course.

    if I go to the page by IP, I can see the page, click the button and it will take me to that service corresponding to the port.
    But when I use the hostname, I see the page, click the button, and then it just times out.

    I take it I have to add these ports somewhere in either front or backend?

    Help appreciated!