Updated server from 1.10 to 1.11 [Mobs corrupt]

PLAY.KAZAURUSNETWORK.NET
I updated my server from Spigot 1.10 to 1.11, the items, skills and/or mobs are all corrupted..
Can someone help me? Thank you <3

THIS ERROR:
05.07 12:28:16 [Server] INFO ... 15 more 05.07 12:28:16 [Server] INFO at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[spigot112.jar:git-Spigot-7d78b81-a867313] 05.07 12:28:16 [Server] INFO at...

Updated server from 1.10 to 1.11 [Mobs corrupt]