If you receive an error message stating there is no active Direct Debit mandate linked to a schedule in NEST, it means there might be an issue with the setup or processing of your Direct Debit. Here's how to resolve it:

1. Verify Setup: Ensure that you have correctly set up your Direct Debit in the NEST portal. You will need to log into your NEST account and navigate to the relevant section to check if the bank account details are correct and active.

2. Processing Time: Keep in mind that new Direct Debit mandates can take up to five working days to process. If you've recently set one up, it may not have been fully processed yet.

3. Confirm with Your Bank: Once the mandate is set up in NEST, it is crucial to check with your bank to confirm that the mandate has been successfully processed on their end.

4. Contact NEST Support: If all details appear correct and sufficient time has passed, yet the error persists, contact NEST support for further assistance. Provide them with all relevant details so they can effectively investigate the issue.

Nest Support details found here.

By following these steps, you should be able to resolve any issues related to direct debit mandates in NEST.