[FR] Indicate reason for failure to download, particularly due to region block

[Konraddo]

Is your feature request related to a problem? Please describe.
I imported a playlist but PF quickly went through the list without downloading anything. It could pull the individual video URL successfully. Eventually, I discovered that I was using VPN in browser and the whole playlist was actually blocked in my region. Then I put PF through Gluetun container's VPN network, and it can download the playlist just fine.

Describe the solution you'd like
Indicate somewhere that the videos are region blocked, even though PF can access the playlist.

Describe alternatives you've considered
N/A

Additional context
N/A