Pixelmon Mod

Hey so im in a server with my friends i found 4 or 5 haunted tower but there was not any Pokemon spawner , anyone knows where i can found them pls

Which version of Pixelmon are you playing? In the 9.x versions all structures have been completely overhauled. Spawner Blocks are no longer necessary, since Minecraft's structure identification on 1.16.5 is solid enough to define dedicated spawns for them via the regular spawning system.