Paypal Order API capture payment in Angular and NestJS - paypal

Question

My stack is NestJS and Angular12, I am using the OrderAPI v2.
I succesfully implemented the order flow using an SDK button, but, since I have several payment systems that are activated by a single button "Pay now", I need to avoid SDK in my front end. Follows the methods I use to create and capture payments, and they works with the SDK button.
async createOrder(value: number): Promise<any> {
const accessToken = await this.generateAccessToken();
const url = this.baseUrl+`/v2/checkout/orders`;
const body = {
intent: "CAPTURE",
return_url: process.env.CLIENT+"/success",
purchase_units: [
{
amount: {
currency_code: "EUR",
value: value.toFixed(2)
}
}
]
}
const headers = {
"Content-Type": "application/json",
Authorization: `Bearer ${accessToken}`
}
const obs = this.httpService.post(url, JSON.stringify(body),{headers: headers});
const response = await firstValueFrom(obs);
return response.data;
}
async capturePayment(order: CreateOrderDto, orderId: string): Promise<any> {
const accessToken = await this.generateAccessToken();
const url = this.baseUrl+`/v2/checkout/orders/${orderId}/capture`;
const headers = {
"Content-Type": "application/json",
Authorization: `Bearer ${accessToken}`
}
const obs = this.httpService.post(
url,
{},
{
headers: headers
}
)
const response = await firstValueFrom(obs);
if (response.data.success) await this.orderService.createOrder(order)
return response.data;
}
When calling the createOrder() function I return the url of the approvation, and in my Front-end I do the redirect to the approve page of Paypal. The problem is that when approving the transaction on the approve url the user is shown a infinite loading page.
Is there something I am missing?