Amazon S3 - How to fix 'The request signature we calculated does not match the signature' error?

I have searched on the web for over two days now, and probably have looked through most of the online documented scenarios and workarounds, but nothing worked for me so far.

I am on AWS SDK for PHP V2.8.7 running on PHP 5.3.

I am trying to connect to my Amazon S3 bucket with the following code:

// Create a `Aws` object using a configuration file
$aws = Aws::factory('config.php');

// Get the client from the service locator by namespace
$s3Client = $aws->get('s3');

$bucket = "xxx";
$keyname = "xxx";

try {
    $result = $s3Client->putObject(array(
        'Bucket' => $bucket,
        'Key' => $keyname,
        'Body' => 'Hello World!'
    ));

    $file_error = false;
} catch (Exception $e) {
    $file_error = true;

    echo $e->getMessage();

    die();
}

My config.php file is as follows:

return [
    // Bootstrap the configuration file with AWS specific features
    'includes' => ['_aws'],
    'services' => [
        // All AWS clients extend from 'default_settings'. Here we are
        // overriding 'default_settings' with our default credentials and
        // providing a default region setting.
        'default_settings' => [
            'params' => [
                'credentials' => [
                    'key'    => 'key',
                    'secret' => 'secret'
                ]
            ]
        ]
    ]
];

It is producing the following error:

The request signature we calculated does not match the signature you provided. Check your key and signing method.

I've already checked my access key and secret at least 20 times, generated new ones, used different methods to pass in the information (i.e. profile and including credentials in code) but nothing is working at the moment.

After two days of debugging, I finally discovered the problem...

The key I was assigning to the object started with a period i.e. ..\images\ABC.jpg, and this caused the error to occur.

I wish the API provides more meaningful and relevant error message, alas, I hope this will help someone else out there!

I get this error with the wrong credentials. I think there were invisible characters when I pasted it originally.

I had the same problem when tried to copy an object with some UTF8 characters. Below is a JS example:

var s3 = new AWS.S3();

s3.copyObject({
    Bucket: 'somebucket',
    CopySource: 'path/to/Weird_file_name_ðÓpíu.jpg',
    Key: 'destination/key.jpg',
    ACL: 'authenticated-read'
}, cb);

Solved by encoding the CopySource with encodeURIComponent()