Google Custom Search API - one request per day only!

I am using the Google Custom Search API for the Image Search Layer project.

It seem there are a limit of requests per day, but for me, from my code it is only one request per day.
After, in the console, it shows this error:

{
“error”: {
“errors”: [
{
“domain”: “usageLimits”,
“reason”: “dailyLimitExceeded”,
“message”: “This API requires billing to be enabled on the project. Visit https://console.developers.google.com/billing?project=875597086590 to enable billing.”,
“extendedHelp”: “https://console.developers.google.com/billing?project=875597086590
}
],
“code”: 403,
“message”: “This API requires billing to be enabled on the project. Visit https://console.developers.google.com/billing?project=875597086590 to enable billing.”
}
}

https://developers.google.com/custom-search/json-api/v1/overview

Says there that you should be able to do 100 searches per day for free. If your API key isnt working then I suggest you get another one.

can also be done on same website

Seems like an issue with the API key. It could also have something to do with the search parameters.
You can read more about it here: https://blog.expertrec.com/google-custom-search-json-api-simplified/

Since the source of the problem is itself unclear, you can try out the things mentioned in the article. It might be a bit beyond debugging here.