@noris, thanks for your note Noris. Like Dylan I too have taken some time out
Your summary of the issue is accurate. Over the (say) two week period after your last note TIDAL was pretty much working perfectly (which goes part way to explaining why I didn’t respond - sorry about that).
I have reactivated port aggregation between switch and NAS. Turning it off didn’t improve the situation and having it on doesn’t seem to make it any worse.
Firewalls/virus apps etc are all set to allow Roon and TIDAL through.
Now changed settings in router to use Cloudfare. This has not any positive effect either in my media room with Project S2 nor in the Study from Surface Book to Oppo HA1.
I’ve already tried connecting NAS directly to router. As per changes to port aggregation this didn’t work either.
As an update my setup has changed a little. NAS, switch, router and Project S2 are still the same . I am now using an Allo USBridge (https://allo.com/sparky/usbridge.html) and my Roon Controller is via a Samsung Tab S4 (Android obviously ).
It may be of interest to note that my issues commenced arounf the time of Roon upgrade 1.5. These issues have always been intermittent. Right now, post 1.6 upgrade, TIDAL is completely dead via Roon. I can play music via TIDAL internet and TIDAL app (on PC, phones and tablet) but nor through ROON.