Bug 507346

SUMMARY
Attepting to play a YouTube playlist with its access policy set to "private" fails silently, with no indication to the user about what went wrong.

STEPS TO REPRODUCE
1. Have a YouTube playlist that is set to "private" (only accessible by the account that created it)
2. Click on "Open URL" in Haruna, paste the URL in the text field and hit Enter/press "Open"

OBSERVED RESULT
Nothing happens, not even a "loading" animation that stops after some time - just nothing.

EXPECTED RESULT
An error message appears, stating that there was a problem playing the content of the URL that was entered, maybe even with basic troubleshooting steps if the exact reason of the failure can be easily determined.

SOFTWARE/OS VERSIONS
Haruna Version: 1.4.0 (Flatpak)
Operating System: Kubuntu 25.04 (Kubuntu Backports PPA enabled)
KDE Plasma Version: 6.3.6
KDE Frameworks Version: 6.14.0
Qt Version: 6.8.3
Kernel Version: 6.14.0-24-generic (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i7-6700K CPU @ 4.00GHz
Memory: 15.6 GiB of RAM
Graphics Processor: NVIDIA GeForce GTX 970
Manufacturer: Gigabyte Technology Co., Ltd.
Product Name: Z170-Gaming K3

ADDITIONAL INFORMATION
Once I change the access policy of the playlist to "Public" or "Unlisted" (aka only accessible if you know the link), everything works as expected.