Bug 491715

SUMMARY

I am on an intranet that requires access to an HTTP proxy with authentication every time I need to access the Internet (either HTTP or FTP protocol). 
The proxy configuration and the user and password it requires are configured in the system proxy (openSUSE's YaST, but it could be any other Linux) and it works correctly. When I update the system or add repositories, I don't need to enter the proxy username and password because the system provides them from the configuration I made previously. Applications that have access to the Internet, such as browsers, even though the username and password are in the system proxy settings, ask for the username and password when accessing the Internet for the first time in the session.

The openSUSE installer does not ask for the credentials, because they are already stored in the system proxy configuration and the Plasma proxy should also use the same ones. Discover, however, prompts for the proxy credentials when launching the proxy. This is not a problem, but it is confusing that if the Plasma proxy takes the system proxy settings, it still requires the user to provide those credentials.

The real problem with this is that only “Discover” asks for credentials, in order to access the Internet. All other native Plasma applications do NOT request the credentials and fail. For example, from "System preferences, Global theme",  if I try to “Get new ...” themes, cursors, color schemes, window decorations, etc, Plasma doesn't show nothing cause is not able to access the Internet and, at best, shows a window with the message “Network error 0: Proxy requires authentication”.

STEPS TO REPRODUCE
1. Configure system proxy
2. Configure Plasma proxy to get same system configuration
3. Launch "System preferences, Global Theme, Cursors" and click on "Get new cursors".

OBSERVED RESULT
A Plasma window showing "An error happened" appears, showing "Network error 0: Proxy requires authentication”.

EXPECTED RESULT
To show downloadable cursors

SOFTWARE/OS VERSIONS (two distint PC and openSUSE version tested)
Operating System: openSUSE Leap 15.6  / openSUSE Leap Tumbleweed
KDE Plasma Version: 5.27.11 / 6.1.3
KDE Frameworks Version: 5.115.0 / 6.4.0
Qt Version: 5.15.12 / 6.7.2
Kernel Version: 6.4.0-150600.23.17-default (64-bit)  / 6.10.2-1-default (64-bit)
Graphics Platform: X11 / Wayland

ADDITIONAL INFORMATION