GET Presigned URL - SignatureDoesNotMatch

Hello,

I am using the AWSSDK.S3, version 3.7.305.30, for Dotnet Core. I have ran into an issue when creating a PreSignedURL, but have been able to perform most other operations through the SDK with no issues.

I am creating the PreSignedURL in a Dotnet Web API, and then sending the result string to a Client Application, which is attempting to embed the result in an <object>/<iframe>/etc.

However, I cannot get this to work. I always get a SignatureDoesNotMatch error. I get the same error, if I copy the result string, and paste it into a browser (i.e. visit the link).

My code is as follows:

var accessKey = configuration.GetSection("AppSettings:StorageAK").Value;
var secretKey = configuration.GetSection("AppSettings:StorageSecret").Value;

var config = new AmazonS3Config
{
      ServiceURL = "https://MY-SPACES-NAME.ams3.digitaloceanspaces.com",
};

var s3Client = AmazonS3Client(accessKey, secretKey, config);

var presignRequest = new GetPreSignedUrlRequest()
{
      BucketName = tenant.TenantStorageBucket,
      Key = id.ToString(),
      Expires = DateTime.UtcNow.AddSeconds(900),
      ContentType = "text/plain",
};

return await s3Client.GetPreSignedURLAsync(presignRequest);