Your issue has been discussed in a similar thread here. You can review it to know the steps to fix this error message.
You can find more information related to the enrollment process in the FAQ.
We recommend reaching out to the School district directly, as each school has a different process and can provide the best steps to move forward when enrolling students. Some districts provide direct links to access the registration forms while others use the PowerSchool Enrollment portal for the registration process.
The PowerSchool Community is a great resource if you have any changes to be made while completing fields within the enrollment form. You can check out the FAQs related to the enrollment process here.