At least once per day (for about a month or so), we get a call from someone trying to register for one of our classes saying they can't get the transaction to go through and the error message is "invalid verification code entered". I also recall someone saying that they got that error as well, but also there was an issue with the captcha. Today, we had 2 calls with this error, but at the same time, we had 8 other registrations that came thru just fine.
