Suddenly...one third of my tracks are 'unavailable' using Qobuz

Guess you're just lucky. I've been running 1 or 2%
Try contacting Qobuz.

wgs57

... my favourite playlist I created using Qobuz and suddenly 20 tracks out of the 63 tracks I have added is now unavailable? I guess Qobuz is like popular video streaming services where movies come and go ...

I have not found that to be the case with Qobuz at all.

I am in Canada by the way ...

That may be the problem - I understand Qobuz is not officially available in Canada.

What tracks seem to be unavailable??

That is not good. As noted above, Please email Qobuz and ask them. Please include the names of some of your missing tracks.

Are you using Roon? Other Roon users have had similar issues. “Sometimes these streaming quirks are fixed by restarting your Roon Core”.

I also suggest you reboot all devices. Power down your modem and router for 2 minutes. Please also ensure all software updates have been applied. If issue continues, please email Qobuz customer support.