I'd like all virtual servers on my server to use RoundCube. So I have created a separate subdomain: webmail.mainsite.tld and bound it to a dedicated IP, different that which mainsite.tld sits on. Everything works, but unfortunately validation gives this error:
Apache website : The Apache virtual host for this domain does not use the IPv4 address and port xxx.xxx.xxx.xx:80
How can I properly replace the system webmail to RoundCube, so that all virtual servers use it?