Hi @extra hyper , Welcome in community
Try to to fix account authentication, open Windows Settings, navigate to System, and select Shared experiences. Look under the Accounts section, and if a button labeled Fix is now visible, click it and re-enter your Microsoft account credentials to restore the session.
Then reset the Phone Link application on your PC, first close the app completely. Open Settings, navigate to Apps, select Installed apps, locate Phone Link, and open its Advanced options. Click Repair to attempt a non-destructive fix, and if the sign-in issue persists, click Reset to wipe the local app cache
Last step, open Microsoft store and check if there are some pending updates, specifically for the phone link app
Let me know how it goes
Elvis