There can be multiple reasons why a learner registration has not been approved.
Incomplete registration - If your registration status is "in draft" you will need to click the 3 dots next to Learner and select "Edit Registration"

No Working with Children Check - If you selected "No, I don't" to having a WWCC, your registration may be declined. To add a WWCC to a registration please use this article the support article HERE to assist.
No Working with Children Exemption - In some cases you may require an exemption for a WWCC. To find out more information about valid exemption types, please see the assigned exemptions between each Member Federation. Please use the support article HERE to assist in requesting an exemption.
Declined Registration - If your registration has been declined, Please reach out to your relevant Member federation for confirmation on why. Once the reason has been confirmed, you can create a new registration.