uh, I thought I had send this post, but obviously not. Sorry that you had to wait ...
for autoconfig.* and autodiscover.* to work you must set the correct DNS settings for each domain you add to mailcow.
if you add the domain
sub.domain.com to mailcow you would have to add DNS A/AAAA or CNAME records for
autodiscover.sub.domain.com. the same applies for every domain. see the linked wiki as a template for the domains you add to mailcow