Got many pool rejected hash

[cron13]

Hi!
I got many messages {"identifier":"error","param":"pool rejected hash"}
I use pool { "url" : "gulf.moneroocean.stream", "port" : 10001, "emptypassword" : "", "algorithm" : "cn"}

Why this can occur?

[Gijs735]

I think I might have a similar/the same problem. Screenshot from moneroocean:

It could be that this is just normal but i'm not sure... Does anyone know why this happens and what to do about it?