Getting {"message":"Missing Authentication Token"}"

Question

I set up a Rest API with resource, 'ANY' method and stage. The Lambda function was tested and the API method  GET (integration request type: Lambda_proxy) , and they both  returned the list i need from a bucket. But when i try to access the API which does not require key, it is set to: "false", I keep getting this message: "{"message":"Missing Authentication Token"}". I looked around for the same problem, saw a similar one but no one ever solved his problem asked 5 months ago.

P.S. There is an IAM role attached to the Lambda function with a AmazonS3ReadOnlyAccess and i even added an additional "bucket_allow" ( the bucket is public).

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "PublicReadGetObject",
            "Effect": "Allow",
            "Action": "s3:GetObject",
            "Resource": "arn:aws:s3:::name_of_bucket"
        }
    ]
}

Answer

You must verify if the URL is as stated in the documentation for Public AWS API Gateway:
https://docs.aws.amazon.com/apigateway/latest/developerguide/how-to-call-api.html

If it's private AWS API Gateway, then you must verify which method you've used and verify its connectivity:
https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-private-api-test-invoke-url.html

Getting {"message":"Missing Authentication Token"}"

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