Howto start usermin remotely to change password

[satimis]

Hi folks,


Ubuntu 7.04 server amd64


I can't figure out how users can start usermin remotely and login their account to change password.


On server, user can start usermin locally running "https://mail:20000"
login in their account and change password.


However on remote PC;
User can browse the apache-default page on server with "http://domain.com" or "http://domain.com"
(remark. homepage NOT hoisted yet)


Run
https://mail.domain.com:20000
Unable to connect



https://domain.com/mail:20000/
Not Found
The requested URL /mail:20000/ was not found on this server.


Please advise how to start usermin remotely for users changing their password. TIA


B.R.
satimis