Nether Difficulty Stuck On Peaceful

Hello, recently I started a Minecraft server on Aternos with the Hard difficulty chosen. Monsters and the difficulty work just fine in the overworld, but when it comes to the nether, it is permanently stuck on peaceful. I have tried all the difficulty commands, but it won't stop being peaceful. No blazes can spawn, or magma cubes, and the hunger is not depleted. I am currently using Spigot / PaperMC, with only the clear lagg plugin enabled, which even when turned off does not fix the problem.