The payment required error displayed when launching an AR experience means that the account it was created on doesn't have access to the premium functionality at this time.
This can happen due to several reasons:
1
You cloned one of the templates that use image tracking while on the Free plan. Image recognition is only available on the premium plans.
2
You created the project during your trial period but didn't upgrade to a premium plan. Your project will become active as soon as you upgrade to the plan that includes the features you've used.
3
You created the project on a premium plan, but your plan failed to renew due to a declined payment. Your project will become active as soon as you upgrade to the plan that includes the features you've used.
4
You've run out of the view limit available on your plan. Please check how many views you have left in the account settings.