POST to s3 presigned URL results in a 403

Question

I am trying to use presigned URLs to upload files to s3.  I have the following code in python that generates the presigned URL then used it to POST a file.  My s3 bucket doesn't have any special setup but I do have a CORS with POST as the AllowedMethods.  When I run the python code I get a 403 and the file is not uploaded.  Any suggestions or pointers to follow to resove this would be greatly appreciated.

```
import boto3
import requests

OBJECT_NAME_TO_UPLOAD = "file_path"

s3_client = boto3.client(
	's3',
	aws_access_key_id = "access_key",
	aws_secret_access_key = "secret_access_key"
)

# generate the presigned URL
response = s3_client.generate_presigned_post(
	Bucket = "bucket-name",
	Key = OBJECT_NAME_TO_UPLOAD,
	ExpiresIn = 60
)

print(response)

# upload to presigned URL
files = { 'file': open(OBJECT_NAME_TO_UPLOAD)}
r = requests.post(response['url'], data=response['fields'], files=files)

print(r.status_code)
```

Oleksii Bebych · Answer

https://docs.aws.amazon.com/AmazonS3/latest/userguide/PresignedUrlUploadObject.html

The creator of the URL must have the necessary permissions to upload that object.

The creator in your code is the entity, where you take this access/secret key from
```
	aws_access_key_id = "access_key",
	aws_secret_access_key = "secret_access_key" 
```

POST to s3 presigned URL results in a 403

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