Error with screen

The problem is that RolePlayAPI is a Sponge plugin. And I, it seems, searched, searched and it seems like the screen is only on the client side ... \ 0_0 / R..P..API writes the data to the cache and the mod should pick it up and display it with text against the background of some picture. What can be done? And better, how can I try to replace it?

public class EchoCommand extends CommandBase {

  @Override
  public void execute(MinecraftServer server, ICommandSender sender, String[] params) throws CommandException {
    if(!(sender instanceof EntityPlayer)) {
      return;
    }
    EntityPlayer player = (EntityPlayer) sender;

    if (params != null && params.length > 0) {
      for (String param : params) {
        FMLClientHandler.instance().showGuiScreen(new PassportScreen(RolePlayAPI.getUser(player.getUniqueID())));
      }
    }
  }

  @Override
  public String getName() {
    return "echo";
  }

  @Override
  public String getUsage(ICommandSender sender) {
    return "command.echo.usage";
  }
}

[12:12:54] [Server thread/ERROR] [Sponge]: Error occurred while executing command 'echo ad' for source EntityPlayerMP['MuffinColor'/26, l='world', x=1926,69, y=81,00, z=2367,33]: java.lang.NoClassDefFoundError: net/minecraft/client/resources/IResourcePack
java.lang.RuntimeException: java.lang.NoClassDefFoundError: net/minecraft/client/resources/IResourcePack
    at org.spongepowered.common.command.MinecraftCommandWrapper.tryExecute(MinecraftCommandWrapper.java:164) ~[MinecraftCommandWrapper.class:1.12.2-2705-8.0.0-BETA-3474]
    at org.spongepowered.common.command.MinecraftCommandWrapper.process(MinecraftCommandWrapper.java:145) ~[MinecraftCommandWrapper.class:1.12.2-2705-8.0.0-BETA-3474]
    at org.spongepowered.api.command.dispatcher.SimpleDispatcher.process(SimpleDispatcher.java:341) ~[SimpleDispatcher.class:1.12.2-2705-8.0.0-BETA-3474]
    at org.spongepowered.common.command.SpongeCommandManager.process(SpongeCommandManager.java:329) [SpongeCommandManager.class:1.12.2-2705-8.0.0-BETA-3474]
    at net.minecraft.command.ServerCommandManager.func_71556_a(SourceFile:1083) [dh.class:?]
    at net.minecraft.network.NetHandlerPlayServer.func_147361_d(NetHandlerPlayServer.java:958) [pa.class:?]
    at net.minecraft.network.NetHandlerPlayServer.func_147354_a(NetHandlerPlayServer.java:937) [pa.class:?]
    at net.minecraft.network.play.client.CPacketChatMessage.func_148833_a(SourceFile:37) [la.class:?]
    at net.minecraft.network.play.client.CPacketChatMessage.func_148833_a(SourceFile:9) [la.class:?]
    at org.spongepowered.common.network.PacketUtil.onProcessPacket(PacketUtil.java:92) [PacketUtil.class:1.12.2-2705-8.0.0-BETA-3474]
    at net.minecraft.network.PacketThreadUtil$1.redirect$onProcessPacket$zld000(SourceFile:539) [hv$1.class:?]
    at net.minecraft.network.PacketThreadUtil$1.run(SourceFile:13) [hv$1.class:?]
    at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_231]
    at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_231]
    at net.minecraft.util.Util.func_181617_a(SourceFile:46) [h.class:?]
    at org.spongepowered.common.SpongeImplHooks.onUtilRunTask(SpongeImplHooks.java:294) [SpongeImplHooks.class:1.12.2-2705-8.0.0-BETA-3474]
    at net.minecraft.server.MinecraftServer.redirect$onRun$zjj000(MinecraftServer.java:3963) [MinecraftServer.class:?]
    at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:723) [MinecraftServer.class:?]
    at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:396) [nz.class:?]
    at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:668) [MinecraftServer.class:?]
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526) [MinecraftServer.class:?]
    at java.lang.Thread.run(Unknown Source) [?:1.8.0_231]
Caused by: java.lang.NoClassDefFoundError: net/minecraft/client/resources/IResourcePack
    at ru.muffincolor.rpm.commands.EchoCommand.func_184881_a(EchoCommand.java:34) ~[EchoCommand.class:?]
    at net.minecraft.command.CommandHandler.func_175786_a(CommandHandler.java:119) ~[bj.class:?]
    at org.spongepowered.common.command.MinecraftCommandWrapper.tryExecute(MinecraftCommandWrapper.java:160) ~[MinecraftCommandWrapper.class:1.12.2-2705-8.0.0-BETA-3474]
    ... 21 more
Caused by: java.lang.ClassNotFoundException: net.minecraft.client.resources.IResourcePack
    at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191) ~[launchwrapper-1.12.jar:?]
    at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_231]
    at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_231]
    at ru.muffincolor.rpm.commands.EchoCommand.func_184881_a(EchoCommand.java:34) ~[EchoCommand.class:?]
    at net.minecraft.command.CommandHandler.func_175786_a(CommandHandler.java:119) ~[bj.class:?]
    at org.spongepowered.common.command.MinecraftCommandWrapper.tryExecute(MinecraftCommandWrapper.java:160) ~[MinecraftCommandWrapper.class:1.12.2-2705-8.0.0-BETA-3474]
    ... 21 more
Caused by: java.lang.NullPointerException