I'm getting that after quite a few rejected shares. Just pause your miner for a couple of minutes and it should be back to normal.
I got about half done swapping over to the Hash Vault pool and it banned me too!
Getting a bit frustrated... I've mined ITNS since Day 2 never had an issue before.
Well... coincidentally today our internet went down for an hour or so due to some network upgrades.
When it came back up I was un-banned from the Official Pool and also Hash Vault.
So I am going to manually assign a fixed difficulty at ~50x hash-rate to each and every miner in the hopes that will prevent any further issues (as suggested in the Slack chatroom).