Problem with braintree dropin in latest istallation

Hi we have just download a trial version of you braintree payment plugin for nopcommerce 4.10 for testing it before proceed to purchase it. We already set up a sandbox in braintree and make the setup . So when using a recurring product (we followed very carefully you instructions) when we submit the payment with demo (but right) credit card detail in the order process , we take the above message
"DropinError: No payment method is available."
We have also enable vault and Vault manager because they are appropriate for braintree for reccuring payments.

Plugin support recurring payments. PayPal team checked it for internal customers several time. Please check if you have other Braintree plugin with old braintree kernel library. Remove it from plugin folder.

Read this topic
https://www.foxnetsoft.com/documentation-braintreedropin#q3

1. Did you create the Plan in braintree admin mode and used nopcommerce product ID as plan ID?
2. Can you tell me if I understood you?
a) Customer opened the checkout in nopcommerce.
b) Customer saw Braintree widget and used sandbox credit card and pressed the button ''Submit payment '
c) Customer saw order confirm page (checkout step) and pressed the button 'Conform order'.