Since last night I am unable to login to Tidal from my roon app on my phone or on my Mac. I’m running Roon on Nucleas. Anyone else have this problem or ideas on fixing it?
Try power cycling the Nucleas as a first step.
Then logout and in again
As mentioned above, definitely give rebooting the Nucleus a try — often it will fix this type of behavior.
If you are still experiencing difficulties after rebooting can you give us some details on your current networking setup including all networking hardware in use?