I can Export mi mods, but i can play it in other versions

Hi everyone, i hope you´re ok. My question is simple, i new in this and i made a simple mod whit a new block that can be use to made a sword. when i test it whit the mcreator works perfectly, but if a export the mod and i try to instal it on another version of minecraft don´t work.

I make sure that all the versions are compatible:

mcreator v1.9.0 to create mods

The launcher that i use is the launcherfenix 5.7.4 and the minecraft version is 1.12.2 whit forge 14.23.5.2768, to try after export the mod

but still dont work.

what could be the problem?

I remain attentive to response, good day!!