Nothing spawning in The Nether, even from a blaze spawner. (on a server)

I'm trying to kill some Wither Skeletons to be able to spawn The Wither, and kill it. But there's one slight issue. No Wither Skeletons are spawning ever, as a matter of fact nothing is spawning. So I went into the debug menu and NOTHING is in this dimension besides myself.

This is... interesting, there's the capability to spawn mobs, but nothing is spawning.

The local difficulty is: 2.25 // 0.13 so mobs should spawn, right? This is also JE, not bedrock.

If you are on a server talk to the owner, they could have disabled nether or if on a server by yourself try resetting nether or destroy the portal and make a new one. If those don't work say something.