I’m using the following code with the AWSSDK.S3 nuget package:

public static string GetPreSignedURL(string filename, string displayFilename)
{
    GetPreSignedUrlRequest request = new();

    request.BucketName = BucketName;
    request.Key = filename;
    request.Expires = DateTime.UtcNow.AddHours(24);
    request.Headers.ContentDisposition = "attachment; filename=" + displayFilename;

    return client.GetPreSignedURL(request);
}

There are no errors running this on the the uploaded file to get a presigned URL, which is returned:

https://mydomain.ewr1.vultrobjects.com/86af3c37-2098-4301-90fc-f79c4c2d559d?AWSAccessKeyId=TWQVOAXAG4K34ITQPM7V&Expires=1719736648&Signature=vJ7ruIafjpEzH1gilFQUOYqnfOM%3D

Now I add the same content-disposition on the end so it will download with the filename I want:

https://mydomain.ewr1.vultrobjects.com/86af3c37-2098-4301-90fc-f79c4c2d559d?AWSAccessKeyId=TWQVOAXAG4K34ITQPM7V&Expires=1719736648&Signature=vJ7ruIafjpEzH1gilFQUOYqnfOM%3D&response-content-disposition=attachment; filename=test1.txt

But this gives an S3 error if I try to follow the link:

<Error>
  <Code>SignatureDoesNotMatch</Code>
  <RequestId>tx00000080074260b914ed7-00667fc9c3-67874bae-ewr1</RequestId>
  <HostId>67874bae-ewr1-us</HostId>
</Error>

Any idea of how to set this up properly? Thanks.