Jitsi (nginx) redirects all traffic to itself


I installed a jitsi server on a domain jitsi.domain

I tried to reach a subdomain like sub01.domain via nginx. This was redirected to jitsi. Either all traffic to port 80 domain or port 443 domain is always redirected to jitsi but in the browser address line is shown port 443 domain. (I changed http resp. https to the port numbers because I am not allowed to quote a link as new user …)

Does that mean jitsi is running as a standalone-server and no other services like postfix/dovecot/apache2 or other virtual domains will run on this machine??