The signature of the user operation is not valid because it is outside of the specified time range.

This error occurs when the block.timestamp is after the validUntil timestamp or before the validAfter timestamp.

Solutions

1. Check that the validAfter and validUntil fields are set to 0 if you aren't using a time-based signature.
2. Check that the validAfter and validUntil fields are set correctly and that the user operation is sent within the specified range.