Mobs not spawning

[Ruudiluca]

Mobs have stopped spawning naturally. Currently, the only way to spawn mobs is through mob spawners (I am currently having to use a dungeon under my home to get mob loot).

I've tried using a mob spawn limit mod to try and increase the spawn limits.

I heard of a bug caused by dimensional doors which was apparently fixed in a more recent version. I tried updating dimensional doors but the issue was not fixed (I have downgraded it again since then).

This is a multiplayer server.