I recently created a mod called Alazeprt's Computer, based on https://fabricmc.net/wiki/tutorial:blocks After creating the block, the game runs crashed
Crash Report:
minecraft.log

Use the JAR file that doesn't have a suffix.

It seems that you are running your mod in a production environment. Which JAR file are you using for the mod? You need a remapped JAR file, so dev and sources will not work.

It seems that you are running your mod in a production environment. Which JAR file are you using for the mod? You need a remapped JAR file, so and will not work.dev``sources

I used the JAR file of dev to load as the mod

Use the JAR file that doesn't have a suffix.

But after the gradle is built, there are only two JAR files, dev and source

Problem solved