You will receive this error when your OpenText Account User Id is not the same as your email address.
The migration to IAM for OpenText Account from September 11th, 2022, has introduced a separate User Id as well as a user email address. Users signing-up for the developer experience and associated developers trials MUST use their email address as their User Id when signing-up, for provisioning of their Trial and their Organization to be successfully completed.
When required to fill in the fields in the screen below, ensure the User Id is set to the email address within the User profile tab.