PayPal API returns RESOURCE_NOT_FOUND / INVALID_RESOURCE_ID but the transaction is listed in the Sandbox Business account - paypal

Question

I have a similar issue.
Setup
PayPal Sandbox environment
Two test accounts (Personal and Business account). During the tests the personal account buys a product. The transaction goes to the Business account.
I created REST API app which is connected to the Sandbox Business account above.
I logged in to: https://www.sandbox.paypal.com/ with the credentials of the Business account to generate a PayPal button. The HTML code of the button is added to my website.
Steps
I open the website and click the PayPal button.
I log into PayPal Sandbox with the credentials of the Personal account.
I complete the payment process.
I log into the Business account and I see that the transaction (order) is listed there. I can see the Transaction ID.
Issue
In all requests to the API I use the Client ID and the Secret of the REST API app which I already created for the purposes of the tests.
After that I opened Postman and I sent the following request to PayPal API to generate an access token (Doc: https://developer.paypal.com/docs/api/get-an-access-token-curl/).
curl -v https://api.sandbox.paypal.com/v1/oauth2/token \
-H "Accept: application/json" \
-H "Accept-Language: en_US" \
-u "client_id:secret" \
-d "grant_type=client_credentials"
So far, so good. Then I send an API request to PayPal APIv1 to get more details about the order. I use the Transaction Id which according to what I read is identical to Order ID.
curl -v -X GET https://api.sandbox.paypal.com/v1/checkout/orders/TRANSACTION_ID \
-H "Content-Type: application/json" \
-H "Authorization: Bearer Access-Token"
and I get this:
{
"http_code": 404,
"body": {
"name": "INVALID_RESOURCE_ID",
"message": "INVALID_RESOURCE_ID",
"information_link": "https://developer.paypal.com/docs/api/orders/v1/#error-INVALID_RESOURCE_ID",
"debug_id": "c02871817abba"
}
}
I tried APIv2:
curl -v -X GET https://api.sandbox.paypal.com/v1/checkout/orders/ORDER_ID \
-H "Content-Type: application/json" \
-H "Authorization: Bearer Access-Token"
and I get this:
{
"http_code": 404,
"body": {
"name": "RESOURCE_NOT_FOUND",
"details": [
{
"issue": "INVALID_RESOURCE_ID",
"description": "Specified resource ID does not exist. Please check the resource ID and try again."
}
],
"message": "The specified resource does not exist.",
"debug_id": "c2c24f91a44fd",
"links": [
{
"href": "https://developer.paypal.com/docs/api/orders/v2/#error-INVALID_RESOURCE_ID",
"rel": "information_link",
"method": "GET"
}
]
}
}
Confusion
The transaction is clearly listed in the Business account but the API says that there no such transaction.
Suggestions/Solutions?
Solution
The default behaviour of the payments initiated via PayPal button (generated with the Business account) is Sale but not Order. For more details about the differences between the two, read here - https://www.paypal.com/us/smarthelp/article/what-are-the-differences-between-the-express-checkout-payment-actions-ts1501
The solution is to make a request to another PayPal API method (check: https://developer.paypal.com/docs/paypal-plus/germany/how-to/show-sale/?fbclid=IwAR30yROZMjKT2LlRgSRuVBMGrjdmN1MGbuJ50rUiUBWwW11FSpGdxk5JNpY#show-sale-details)
Here is the request returning correct data.
curl -v -X GET https://api.sandbox.paypal.com/v1/payments/sale/TRANSACTION_ID \
-H "Content-Type: application/json" \
-H "Authorization: Bearer Access-Token"

Answer 1

Solution
The default behaviour of the payments initiated via PayPal button (generated with the Business account) is Sale but not Order. For more details about the differences between the two, read here.
The solution is to make a request to another PayPal API method check this
Here is the request returning correct data.
curl -v -X GET https://api.sandbox.paypal.com/v1/payments/sale/TRANSACTION_ID \
-H "Content-Type: application/json" \
-H "Authorization: Bearer Access-Token"

Answer 2

v2/orders objects are for payment approval only, they are not transactions. Their IDs should only be persisted about a month for debugging purposes, as they serve no accounting purpose and are not referenceable in PayPal.com
A PayPal transaction on the other hand is represented by a v2/payments object, returned when you capture a v2/order. You can get a capture's details again with the appropriate GET call: https://developer.paypal.com/docs/api/payments/v2/#captures_get

Answer 3

It is very likely something is broken on PayPal server. It is happening quite often.
They usually fix it, some time it takes longer than reasonable.
In any way to make sure you are doing everything correctly, and to check if they have problems at the time of your experiments, you can contact paypal support
https://www.paypal-support.com/