Customers receive an Invalid key error when attempting to reset their password.
This error appears in the account login/recovery page when a customer attempts to reset their account password. It occurs when the key passed in the request does not match the generated password reset key created by Shopp when the customer made the reset request. This is part of a security mechanism to ensure that the individual attempting to reset an account password is, in fact, the account owner. If the key provided when loading the page does not match, the reset link may have expired, or may never have been generated in the first place.
The only time this error would indicate a problem with the Shopp installation is when customers report that they are unable to reset their password at all and continue to receive this message. In that case, diagnosis is best left to someone familiar with Shopp and may warrant a support request to the official support team on the Shopp Help Desk.