I had similar issues with Qobuz last week. Playlists had been skipping files for a few days then Roon could not login to Qobuz. Power cycling network and NUC did not help. Decided to try clearing the cache and that did work. I had to go to Settings - Services and setup/login to Qoboz for the auto login to work.
Qobuz has worked since then with no skips. Don’t know why but it worked.
@Mike_LC 's comment about clearing the cache is worth trying. See:
The cache folder is in the RoonServer folder for a Nucleus.
Use the Web Administration Page of the Nucleus to stop Roon Server, then use your Windows File Explorer to access the Nucleus’s folders over the network. Move the Cache folder out from the RoonServer folder to your Windows desktop, then restart the Roon Server. The Cache folder will be re-created and hopefully you should be able to sign in to Qobuz once more…
Glad it worked. The problem is that it is a rare glitch that affects a few people. Tracking down the cause and fixing it is tricky. Roon Labs may be investigating, but resources may be limited. However, it does look as though this workaround of re-creating the cache is useful to try in these cases.
In which case, I suggest that you open a new support request here in the #support category of the forum. The Roon @support team prefer one topic per customer’s issue… so they are able to track it and focus on each individual problem.
In order for Roon’s support team to assist you better, please provide a brief description of your current setup and the nature of the issue using this link as a guide.
Make sure to describe your network configuration/topology, including any networking hardware currently in use, so they have a clear understanding of how your devices are connected. Thanks.
Restart Router, restart core, clear cache, re-launch Roon and try to sign in again. If that doesn’t do the trick for you please follow the advice from @Geoff_Coupe to ensure we have all the information necessary to troubleshoot and gather logs.