Nether Roof spawn rates

[tehnoobisaac]

I'm trying to build a donut gold farm on the nether roof on my server, but little to no zombie pigmen ever spawn there. I was wondering if there was a configuration that restricts spawning on the nether roof, or if there is a way to increase the mob cap or mob spawn rates on the server. Thanks!

[fjsu]

I believe that spawning on the nether roof has been altered in 1.15.2, unrelated to Minehut, could also be related to the mob cap if there's other players on your server actively playing!