Bad packet id 14 on port 25565

Hello, after doing a few world edits on my server, all the sudden everyone gets kicked with "bad packet id 14" i have no clue why this happened, we haven't changed any plugins/configs for the past 2 weeks. the only thing that i can possibly think of is a server attack. as we literally just recovered from a ddos.

What we have done:
Reboot the server
remove all plugins
change the world
redownload server
changed the port

what worked:
changing the port

the server works just fine when we change the port from anything but port 25565.

If anyone would have any clue what is causing this, please help by replying!

Thanks
~Jake, Twisted420