Directional light on Landscape leaves horizon unlit


I’ve been banging my head against the wall for over a day now over this issue.

When trying to light a landscape object with directional light, the landscape remains completely unlit at steep angles from a certain distance. Without the steep angle, it lights just fine (excuse the shoddy lighting at its current state).

I’ve checked virtually all settings that are readily available to tweak. Absolutely nothing works. It looks very much like an issue with lighting draw distance specifically on landscape objects, but I could be wrong.

How can I fix this?