On SCO OpenServer5, I used resin to establish a web server. With listening port 8080, everything is right. But I want to change the port to 80. After I modified resin.conf and restart resin, it gives the following error message and failed to start:

http can't bind to *:80. Check for conflicting servers.

But I think there is not any other server listening on port 80 (How to check that?), because I disenabled httpd in /etc/inetd.conf.


Maybe it is caused by the privilege. I installed resin by user "resin", not the root user.
How can I make resin listen on port 80?