​The most common reason for a mandate registration failure on CubePlus is the browser’s default pop-up blocker preventing the redirection required to complete the mandate setup.

To resolve this, disable the pop-up blocker on your browser. Here's how to do it on Google Chrome (Web):

1. Click on the three-dot menu (⋮) at the top-right corner.
2. Go to Settings.
3. Navigate to Privacy and security.
4. Select Pop-ups and redirects.
5. Choose Sites can send pop-ups and use redirects or add CubePlus to the allowed list.

Once the pop-up blocker is disabled, revisit the mandate creation flow and try again. Make sure you complete the authentication steps after redirection to ensure successful registration.​