It shows that the NBTAPI package has not been moved although from what I see I DID move it according to what the guide said... (Shading The Plugin Problem)

[MSitiSoftware]

Here's what I added and what is currently written in my pom.xml file that I guess is supposedly related to the NBTAPI shading:
This in :

<plugin>
       <groupId>org.apache.maven.plugins</groupId>
       <artifactId>maven-shade-plugin</artifactId>
       <version>3.6.0</version>
       <executions>
         <execution>
           <id>shade</id>
           <phase>package</phase>
           <goals>
             <goal>shade</goal>
           </goals>
         </execution>
       </executions>
       <configuration>
         <relocations>
           <relocation>
             <pattern>de.tr7zw.changeme.nbtapi</pattern>
             <shadedPattern>me.negai.wanddesigner.nbtapi</shadedPattern>
           </relocation>
         </relocations>
       </configuration>
  </plugin>

And this in dependencies:

<dependency>
      <groupId>de.tr7zw</groupId>
      <artifactId>item-nbt-api</artifactId>
      <version>2.13.1</version>
    </dependency>

And this on onEnable method in the plugin's main class:

        @Override
	public void onEnable() {
		if (!NBT.preloadApi()) {
	            getLogger().warning("NBT-API wasn't initialized properly, disabling the plugin");
	            getPluginLoader().disablePlugin(this);
	            return;
	        }
         }

Here is what it showed in the logs

[tr7zw]

Look inside the jar, also do you actually build with maven and not the ide?

[MSitiSoftware]

Look inside the jar, also do you actually build with maven and not the ide?

What do you mean by looking inside the jar?
And no I don't build with the IDE I build it with maven can it be the problem that causes this?

[tr7zw]

Look inside the jar if it is actually relocated or not. Like the actual file paths.

[MSitiSoftware]

Look inside the jar if it is actually relocated or not. Like the actual file paths.

Oh I think now I see, there are 2 packages here, me.negai.wanddesigner (my package) and de.tr7zw.changeme.nbtapi... I guess it means it wasn't relocated right?

[tr7zw]

Correct. That means it didn't work/run. Check the output when running the mvn clean install command.

[MSitiSoftware]

Correct. That means it didn't work/run. Check the output when running the mvn clean install command.

I succeeded in fixing this, thank you so much for helping!