Project has not been linked in Google play developer console, error came while I called the Google Developer API

I have integrated Google In-App subscription in one of my apps. It was integrated successfully. But, one mistake I have made while making subscription plans without a linked project with Google Play Developer Console. I found the same issue's answer on stackoverflow and everyone said that first link your project and then start to create subscriptions plans. I created a few more plans after the project linked, but this issue yet not fix.

Below, I have attached error snippets

Here, I saw you exact steps that I have performed.

1. At first, we made two plans(in-app product, subscription) and then we linked the project through google play console.
2. When we hit the google play developers API, we get error 403, "Project Id not linked to google play".
3. After searching through StackOverflow, we got to know, first, the project is to be linked and then the subscription plans are to be added. So we made two more plans in the project after linking it.

However, the error still persists.

Can you please help us with why this error is coming despite the project being linked and subscription plans made after linking that project?

The below added are links that we refer for the solution. The API URL that we use: Purchases.subscriptions: get and Inappproducts: get

Also, here I have attached stackoverflow and GitHub links which have the answers on the same issue that I already tried:

Error: 'The project id used to call the Google Play Developer API has not been linked in the Google Play Developer Console.'

"message": "The project id used to call the Google Play Developer API has not been linked in the Google Play Developer Console."

https://github.com/googleapis/google-api-php-client/issues/1529

Please help me to resolve this issue.

Thank you.

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