could not start server issuse

[S1mple133]

I am getting this error:
[16:54:01 INFO]: [JSONAPI] Enabling JSONAPI v5.6.0
[16:54:01 INFO]: [JSONAPI] Logging to file: false
[16:54:01 INFO]: [JSONAPI] Logging to console: true
[16:54:01 INFO]: [JSONAPI] IP Whitelist = None, all requests are allowed.
[16:54:01 ERROR]: [JSONAPI] Couldn't start server!

[16:54:01 WARN]: java.net.BindException: Address already in use: JVM_Bind
[16:54:01 WARN]: at java.net.DualStackPlainSocketImpl.bind0(Native Method)
[16:54:01 WARN]: at java.net.DualStackPlainSocketImpl.socketBind(Unknown Source)
[16:54:01 WARN]: at java.net.AbstractPlainSocketImpl.bind(Unknown Source)
[16:54:01 WARN]: at java.net.PlainSocketImpl.bind(Unknown Source)
[16:54:01 WARN]: at java.net.ServerSocket.bind(Unknown Source)
[16:54:01 WARN]: at java.net.ServerSocket.(Unknown Source)
[16:54:01 WARN]: at java.net.ServerSocket.(Unknown Source)
[16:54:01 WARN]: at com.alecgorge.minecraft.jsonapi.NanoHTTPD.(NanoHTTPD.java:277)
[16:54:01 WARN]: at com.alecgorge.minecraft.jsonapi.NanoHTTPD.(NanoHTTPD.java:302)
[16:54:01 WARN]: at com.alecgorge.minecraft.jsonapi.JSONServer.(JSONServer.java:54)
[16:54:01 WARN]: at com.alecgorge.minecraft.jsonapi.JSONAPI.onEnable(JSONAPI.java:525)
[16:54:01 WARN]: at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:321)
[16:54:01 WARN]: at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:340)
[16:54:01 WARN]: at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405)
[16:54:01 WARN]: at com.rylinaux.plugman.util.PluginUtil.load(PluginUtil.java:285)
[16:54:01 WARN]: at com.rylinaux.plugman.command.LoadCommand.execute(LoadCommand.java:114)
[16:54:01 WARN]: at com.rylinaux.plugman.PlugManCommandHandler.onCommand(PlugManCommandHandler.java:104)
[16:54:01 WARN]: at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
[16:54:01 WARN]: at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141)
[16:54:01 WARN]: at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchCommand(CraftServer.java:641)
[16:54:01 WARN]: at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchServerCommand(CraftServer.java:627)
[16:54:01 WARN]: at net.minecraft.server.v1_8_R3.DedicatedServer.aO(DedicatedServer.java:412)
[16:54:01 WARN]: at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:375)
[16:54:01 WARN]: at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:654)
[16:54:01 WARN]: at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:557)
[16:54:01 WARN]: at java.lang.Thread.run(Unknown Source)

Help pls