Your email has been flagged as invalid, either because it does not exist, or the inbox was full when we tried to send you a message, or it was flagged as suspicious. It means that for example password recovery via email will be disabled. Please contact us if you are willing to resolve this issue.
As of now, it is not known whether your email is valid or not. Password recovery and notifications will be sent by default, and mail feedback will be monitored. Automated validation will be implemented later.