Welcome to the community! I’ve moved your post over to this topic thread as this is specifically for djay Pro on Windows.
Could you please first confirm that you have an active and valid TIDAL account (Premium or HiFi). The easiest place to check this is to go to listen.TIDAL.com and then sign in. To view your subscription, click on the … next to your name, then on Manage Subscription; if you have an active subscription you will see a screen with a billing date mentioned above your selected subscription.
If this is active, then could you please confirm that you are you able to log in to TIDAL outside of djay and play your music without issue.
If you can confirm both of those things, then could you please try logging out of TIDAL in djay by clicking on “Media library settings” in the djay Pro settings menu, select “Log out of TIDAL”, and then log in to your TIDAL account again in djay by accessing the TIDAL library?
If the issue persists, please post a screenshot of any error message you receive or what happens exactly when you try to log in to TIDAL in djay Pro so I can help you out further.