# InvalidWorkBlock (/docs/errors/chain/InvalidWorkBlock)

The `block_number` in the proof-of-work submission is in the future or more than 3 blocks old, so the work is stale. Compare the submitted block number with the current chain height and regenerate the PoW against a fresh block.

Declared by the `SubtensorModule` pallet; it classifies to the semantic code [`invalid_argument`](/docs/errors/invalid-argument).

## Remediation [#remediation]

Check the argument values against the operation schema

The same explanation is available in the terminal: `btcli explain InvalidWorkBlock`.