Low spawn rates in gold farm

So I made a gold farm (without portals) and followed all the instructions correctly but I got only a few xp and drops from that. I don't know if it is the render distance, I already set the server's render distance to 10 (the maximum) but the farm needs minimum 12 render distance. However when I build the exact same thing on my singleplayer world it works just well with 10 render distance. Like it is so different, in singleplayer I can get 5 levels in just a matter of seconds. This one in my server is so slow. Any help or ideas what is going on?

Turns out that I messed up with the spawn limits and now it works fine.
Fixed