Invalid move player packet recieved

I have a server using Aternos which is a free server maker for the people who are too lazy to code it, today I tried to go onto my server and it came up with "Invalid move player packet received" and I'm quite confused. The only thing I did last time I went on my server was loaded in a new server world for a starter lobby someone had made. Now, whenever I try to go onto it kicks me with that message? I have seen other people with this problem but not in the same context. I have never had this problem before but are there any fixes?