Question

i already download every thing but it didnt work i dont know why

Also found this to be the case with Neoforge 1.21.1, while building my modpack.
(Just sharing the loader version, in case someone else can test this better before I can.)

I'll post more details when I get an opportunity to try test it without other mods or try figure out which other mods might be causing the issue.
(Can't run my Minecraft right now to do so immediately.)

Might be related (better described) in this ticket: #283

Seems to be an incompatibility issue with "Clean Tooltips". After I removed that, it worked.