Client mod work only on singleplayer

[tovac]

Hello. I want to write a client mod (for version 1.12.2), which simply print "Break!" in the game console when some player (not only me) breaks a block. I used this documentation, but I ran into a problem.
Here is the mod code:

@Mod(modid = ExampleMod.MODID, name = ExampleMod.NAME, version = ExampleMod.VERSION)
public class ExampleMod 
{
    public static final String MODID = "examplemod";
    public static final String NAME = "Example Mod";
    public static final String VERSION = "1.0";
    private static final Logger logger = LogManager.getLogger(ExampleMod.MODID);

    @Mod.EventHandler
    public void init(FMLInitializationEvent event) 
   {
        logger.info("Started");
        
    }
}

@Mod.EventBusSubscriber(modid = ExampleMod.MODID)
class TestHandler {
    private static final Logger logger = LogManager.getLogger(ExampleMod.MODID);

    @SubscribeEvent
    public static void onBlockBreak(BlockEvent.BreakEvent event) {
        logger.info("Break!");
    }
}

The problem is that the mod works in singleplayer mode, but stops working when I go to the server. In multiplayer, I do not receive block breaking events, either from other players or from myself.
It seems to me that the mod is loaded as a server one. But I did not find a way to explicitly indicate that the mod should be loaded as a client one.

[eMigrowsLy1]

In multiplayer, BlockEvent.BreakEvent is called only on the server. The client does not receive these events.