Minecraft Server Bug 1.8.8

I have a problem with a launcher original Minecraft version 1.8.8 (no mod) just within the server (vanilla with plugin) where Helper lets me write for 10-20 seconds and then I "lags" (I have a connection 30 mega 3 upload and low ping servers on about 50) and says connection lost "disconnected" without writing another I tried with another launcher unofficial and it worked great I tried again with another server (with the official launcher and worked great) what can I do?