Will not let me join a specific server

What I expected to happen was...:
I would be able to join a server like usual

What actually happened was...:
I clicked join server and this popped up:
connection lost
Internal Exception: io.netty.handler.codec.decoderexception: com.google.gson.JsonSyntaxException: com.gson.stream.MalformedJsonException: Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 2

Steps to Reproduce:
1. Open Minecraft
2. click multiplayer
3. Click server