I can't login to a minecraft server.

I'm useing Optifine 1.9.4 HD U B5
I tried reinstalling my Minecraft and useing it without Optifine and it's still the same.
When I try to login to a server it writes this message: Internal Exeption:io.netty.handler.codec.DecoderExeption:com.google.gson.JsonSyntaxExeption:com.googlegson.stream.MalformenJsonException: UseJsonReader.setLenient(true) to accept malformed JSON at line 1 column 2.
Sometimes I can get into servers but after 5-10 minutes I get kicked with that message.