S3 Presigned URL doesn't work from newly created buckets

Question

Problem description (Python 3.12): **13-Sept:** Created a new "bucket_1" (AWS console), added a new "file_1" (AWS console), created a presigned URL to get the "file_1" from "bucket_1" (AWS boto3). Link doesn't work. Error: SignatureDoesNotMatch The request signature we calculated does not match the signature you provided. Check your key and signing method. .......... **14-Sept:** Created a new presigned URL for the old (yesterday's) "file_1" from the old (yesterday's) "bucket_1" (AWS boto3). Link works fine (the same code, same IAM user, same computer). **14-Sept:** Created a new "bucket_2", added a new "file_2", created a presigned URL to get the "file_2" from "bucket_2" (AWS boto3). Link doesn't work. Error the same (SignatureDoesNotMatch). **14-Sept:** The old "file_1" added to the new "bucket_2" (AWS console), created a presigned URL for the "file_1" from "bucket_2" (AWS boto3). Link doesn't work. Error the same (SignatureDoesNotMatch). Were checked: - credentials (the same account) - permissions (IAM user has "Administrator access") - naming of the buckets and files are unchanged - region of the bucket and bucket creator are the same - signing method (by default it is "SigV4" in boto3) - using AWS CLI gives the same result - **BUT**: directly creating presigned url in the AWS console always works fine I can't imagine where to look. Any help would be appreciated.

Riku_Kobayashi · Accepted Answer

Hello.

What code are you using to issue Presigned URLs?  
I answered a similar problem a while ago, but at that time I was able to resolve it by specifying "endpoint_url" when creating the S3 client.  
https://repost.aws/questions/QUxFKBL7VwSomPT1thHt6qLg/pre-signed-url-timezone-put#ANuoLZPqTsRv-qu4eWLc67-A  
```
s3_client = boto3.client('s3',region_name="eu-central-1",endpoint_url="https://s3.eu-central-1.amazonaws.com")
```

Giovanni Lauria · Answer

It may be that you fell into a specific case of limits within the presigned URLs of S3 as specified in https://docs.aws.amazon.com/AmazonS3/latest/userguide/using-presigned-url.html#PresignedUrlUploadObject-LimitCapabilities

Can we look at the code you use so we can spot anything in there?

S3 Presigned URL doesn't work from newly created buckets

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