Drupal user redirected to MoneyScript checkout page after registration -

We are registering users in our Drupal system through third-party system through REST service call. What happens is that the user is redirected to "MS / Checkout" after registration and a 403-prohibited message is received and any ideas about why this can be fixed:

The issue of this permission may go to the permissions page and allow the unique user to access the cart, checkout page Please give it.