What I expected to happen was:
mobs would be spawning

What actually happened was:
They did not spawn

Steps to Reproduce:
One day they all just disaperared and just stopped spawning

I've looked at other reports of this problem for the fish, but they were all from 1.14. I tryed the fix anyway(adding [ocean_reviver.zip] to the world) but it did not work

Also no harmful mobs are are spawing