This error pops up when Chargebee's Test Gateway is set as the default gateway in the smart routing rules. The parameter card[tmp_token] isn't supported for Chargebee's Test gateway.
To resolve this, on your TEST site, kindly navigate to Settings > Configure Chargebee > Payment Gateways > Smart Routing > Manage Rules and select Stripe for Card Payments.
Once you've set this up, you should be able to process test payments successfully on your Chargebee TEST site.
I have taken the clone from The github link of code sample and added my api key and site in environment file and I visit the link http://localhost:3200/stripe-popup-js/signup.html and submit the form and change the plan id in the controller to my plan id still that is not working why please help got stuck
#<ChargeBee::APIError: Passing card[tmp_token] not is supported for the gateway chargebee>
Why i am getting the above error