I Can't Sign in to CK-12 with My Login Credentials Did you enter the email address associated with your CK-12 account? When you registered for a CK-12 account, we sent an email to the address you gave us. If you can't find the email we sent you, please check your spam or junk folder. Can't remember your password? We'll send you instructions on how you can reset your passwordStill stumped? Email firstname.lastname@example.org for help.