This may not be related to LuckPerms, I already opened a ticket on it, but since no one seemed to be capable of helping, I opened a thread a few days ago on spigot:

https://www.spigotmc.org/threads/mariadb-issues.348153/

If you find this could have something to do with luckperms, or have any advice I'd appreciate it. Luckperms seems written all over the errors, but it could still be a mariadb issue.

Hi,

A couple of the errors are related to LuckPerms.

If you have a look here : https://github.com/lucko/LuckPerms/wiki/Storage-system-errors#mysql-no-operations-allowed-after-connection-closed-error

Then also check out the this page: https://github.com/lucko/LuckPerms/wiki/Storage-system-errors#luckperms-cannot-connect-to-my-mysql-server

An pay close attention to the part about communication link failure.

same problem here: #1295 , everyone says I'm using the wrong username and password, but the username and password is actually correct, hope someone can help.

Using the MySQL root user will not work under certain circumstances. And it shouldn't be used for basic database access anyways.

@Imortalshard Sorry for late answer, I already did everything you suggest, without success.
@BrainStone I personally wasn't. I am now, it makes no diference.
@tianji1993 My error doesn't seem related to yours.

The best help I can give you is written out in full here: https://github.com/lucko/LuckPerms/wiki/Storage-system-errors#mysql-no-operations-allowed-after-connection-closed-error

Those errors aren't being caused by LuckPerms - it's purely a configuration / database caused problem.