If your having issues accessing either webmail or CPanel it could be because that the network your on (corporate network or university) that requires PROXY access or only allows port 80/443 (HTTP/HTTPS) traffic.
If so, then try to access them via the following URL's:
- CPANEL: http://cpanel.domainname.com.au - once logged in, you should be able to use most of the CPanel functions, except File Manager.
- WEBMAIL: http://webmail.domainname.com.au - once logged in, select "RoundCube" icon