2650854 - AS Java administration pages can not be opened - Service cannot be reached - HTTP 404 - Not Found

When trying to open e.g. http://<hostname>:<port>/nwa or http://<hostname>:<port>/sld, they fail with HTTP error:

Service cannot be reached
What has happened?
URL call was terminated because the corresponding service is not available.
Note
The termination occured in system wih error code 404 and for the reason Not found.
What can I do?
Please select a valid URL.
404 - Not found
Your SAP Internal Communication Framework Team

See example screenshot below:

Dual stack system or a system, which was dual stack, and it has been splitted/upgraded to SAP Netweaver 7.4 or 7.5.

logon, error, 404, not found, HTTP 404, Internet Communication Framework, icf, NWA, SLD, service cannot be reached, Virtual Hosts/Services, External Alias, nsicf, , KBA , cannot logon nwa sld , BC-CST-IC , Internet Communication Manager , Problem