It sounds like you are using a ‘Stationary’ Directional light and trying to use both ‘Static’ and ‘Dynamic’ shadows, but have not set up their transition distances yet.
Shadow Casting
The documentation link has some helpful information about this approach, and how to get your shadows to display correctly by modifying your Cascaded Shadow Map settings.
Let me know if you are still having issues, or if you need further assistance.
Thanks,