Internal-Server-Error

Hello. I am realizing that openfire is displaying the same error multiple times. This error causes the spark client to disconnect and connect.
In the log file (attached), it shows that the error has occurred 140 times since 22-07-2019. Could you help me figure out the cause of this error and how to fix it?

ps: the language is brazilian portuguese.

error.log (675,4,KB)