I'm having trouble connecting to 1 minecraft server ArkhamNetwork.

Whenever I try to connect to the ArkhamNetwork server , it pulls up a message saying:

Connection
InternalException:io.netty.handler.codec.DecoderException:com.google.gson.JsonSyntaxException:com.google.gson.stream.MalformedJsonException:UseJsonReader.setLenient(true) to accept malformed Json at line 1 column 2

Please Help Me. Thank You.