Checkout stuck in processing mode

[newhub-spec]

Description:

The project was installed successfully in Vercel with Host & Stripe Test Key variables. I can add products to the cart but pressing checkout button go in Processing...

I have included the Stripe domains in CORS allowed list of GraphQL plugin setting. However, it is still showing the errors.

In Chrome, it is only showing Proxy errors which is the last line of above Mozilla console screenshot:
{
"client": "default",
"operationType": "query",
"operationName": "getStripePaymentIntent",
"statusCode": 200,
"gqlErrors": [
{
"message": "Internal server error",
"extensions": {
"category": "internal"
},
"locations": [
{
"line": 3,
"column": 3
}
],
"path": [
"stripePaymentIntent"
]
}
]
}

I will appreciate the solution to make this great project working.

Thanks & regards.