I deployed Roon server on my Synology NAS, but when choosing to log in by the NAS server, there is a webpage jump to select my roon account, followed by a jump to the roon client on my mac computer, at which point it keeps displaying a prompt to log in without logging in successfully, whereas I have no problem logging in if I select my mac as the roonserver!
This is about the most thorough existing thread I could find on this topic, and you probably don’t have the same problem as the original poster, but if you follow the suggestions in the earlier part of this thread about clearing browser caches and cookies, you might be able to solve your problem…
Gave up a year ago and bought a new Mac Mini M2 with 16 gb memory. No problems with it and Roon runs much faster and smoother. Also no need to reboot Roon after updates. I got 10 years service from the old Mac Mini so no surprise it was time for an upgrade.
Login loops are usually just the fault of an adblocker or other content blocker in the browser that prevents the re-direct from properly resolving. This causes a refresh of the same login page despite entering credentials.
Try clearing your cookies and disabling adblockers temporarily in the default browser on the Mac. See if you can login to the Roon accounts page, which uses the same SSO.
Please let us know if this helps. We’ll watch for a response.