> ## Documentation Index
> Fetch the complete documentation index at: https://jiffyscan.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# AA22: Time-Based Signature Mismatch

> Addressing timestamp-related signature issues in user operations

Your user operation's signature is invalid due to a timestamp mismatch. This occurs when:

* The current `block.timestamp` is later than the `validUntil` time
* The current `block.timestamp` is earlier than the `validAfter` time

These time constraints are derived from the `validationData` (a `bytes32` field) returned by the smart account's `validateUserOp` function.

## Resolution Strategies

1. For Time-Sensitive Operations:
   * Double-check your `validAfter` and `validUntil` settings
   * Ensure your operation is submitted within the specified timeframe

2. For Standard Operations:
   * Set both `validAfter` and `validUntil` to `0`

<Note>
  Pro Tip: For non-time-sensitive operations without aggregators, simplify your `validateUserOp` function:

  * Return `uint(0)` for valid signatures
  * Return `uint(1)` for invalid signatures
</Note>