First, make sure that your chosen service provider is registered with the CRCESU and has provided you with a valid NAN code.
If neither of these are the issue, it may be that your service provider is not yet set up to receive digital CESU benefits. They can change these settings easily on the CESU website:
The service provider must log into their account with the username, NAN code and password provided by the CRCESU,
Click on Dépôt direct (Direct deposit) in the menu on the left,
Accept the general conditions of service.
You should then be able to add the service provider to your beneficiary list.