Amazon MWS - request signature calculated does not match the signature provided

In my experience, this error just means "One of your parameters is wrong, good luck finding it!" I ran into this error using the S3 SDK. I was trying to upload a file but I mistakenly supplied the full file path ("C:\Users\addaone\image.png") as the Key instead of just the file name.

If you are landing here from Google after starting to work through some of the Amazon documentation, it's quite likely that you're seeing the 'request signature' error above due to a inadvertent leading or trailing space on your secret access key. Check that first!

The solution was to generate a new Access Key. My first AWSSecretKey had trailing forward slashes on it that probably were causing the issue, while the new one didn't have any forward slashes and worked.

I ran into this problem as well. For me it's because I accidentally put a / in front of my bucket name.

instead of test/foo/bar I had /test/foo/bar for my bucket name.