Minecraft Server Crashing when players join - The server worked for 24+ hours before

Whenever I open my server and we join the server crashes with the error:

java.lang.StackOverflowError

Crash Logs of the latest 3 tries:

https://drive.google.com/open?id=1a2q_7ER6AlynF7CfILLtl8wKH1UCvGWr

https://drive.google.com/open?id=1J4BA97bvqov-7ds0dlxwYK37kPxLVE3U

https://drive.google.com/open?id=18i9FSOyodytEaFcCL2F_wZnGKUqhgOYS

The server's World:

https://drive.google.com/open?id=1m_3vQIvHxIuZctvuN_kbFn29gRYkDZyE