I tried to build a very simple and manual mob farm in Minecraft. A few blocks up, a large, dark area at the top with water channels in between. The problem is not that the mobs don't fall down, they don't spawn at all. I play normal on the difficulty and have illuminated all possible caves in a huge area. As a test, I even set up 4 mob spawners for zombies, but not even these work. After a while, a mob, nothing else. Do you have any tips or tricks?
The farm must be 3 blocks high and completely darkened on all sides, otherwise the light level is too high. You can also only spawn on whole blocks and not on water or half-steps. If this is on a server, it could be due to the server settings and mob restrictions. The player must also be nearby to spawn, for example under the farm. Mostly the failure is due to a construction error and too much light (e.g. Torches or windows inside).
For more detailed information, you would need more information and, above all, pictures of your mob farm. Also check out the Minecraft Wiki, there's a lot about the requirements of mob farms.
