I cannot log in in the STLAI website
STLAI is hosted on a different site from STLFLIX, as they are distinct products.
The login site is this: https://ai.stlflix.com/login
Note that, being different products hosted on separate domains, the login credentials are also different.
As soon as you purchase any STLAI plan, the login credentials will be sent to the email registered during the purchase. You can then change the password associated with the account.