Also in my case Tidal streaming stopped working after upgrade to Roon 1.8 (build 756).
I was playing tidal library 100% recently…
The albums appear in search but on playback tracks are skipped with ‘non available’ message.
A log sample from server:
02/15 21:29:18 Warn: [tidal/http] GET https://api.tidal.com/v1/tracks/87365297/playbackinfopostpaywall?countryCode=PL&audioquality=NONE&assetpresentation=FULL&playbackmode=STREAM => NotFound
02/15 21:29:18 Warn: [tidal/media] could not get playback info for 168:0:87365297: Result[Status=NotFound]
Server is running on Arch Linux on intel