Did you sign up for your PTI account using a different email address? Most "I can't log in" problems result from trying to log in with a different email address from the one you signed up with.
If you've forgotten your password please click here* and follow the prompts to reset your password and get logged back in to your PTI account.
*If you're unable to use the link above copy and paste the following URL into your browser's address bar - https://accounts.forte.io/forgot-password