CAPTCHA validation error

That's a CAPTCHA error, not specific to the Hidden CAPTCHA.

The main reason why it happens is because the session times out and when the CAPTCHA is finally used, it's too late.

My solution in captcha/captcha.module is to make the time longer... Replace the 84600 below with a larger number (i.e. 84600 * 7 for 1 week). Try that and see if it fixes the problem. It appeared for me because I use Boost.

/**
 * Implementation of hook_cron().
 *
 * Remove old entries from captcha_sessions table.
 */
function captcha_cron() {
  // remove challenges older than 1 day
  db_query('DELETE FROM {captcha_sessions} WHERE timestamp < %d', time() - 84600);
}

Thank you.
Alexis Wilke

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