PHP图像上传到AWS S3存储桶不工作，困惑？

I'm trying to upload an image to an AWS s3 bucket that I have created, so I have copied an pasted the standard code from the AWS documentation to accomplish this but I get an absolute blank page. Like even if I put an echo 'hi' before any statements, even that doesn't show up. Wondering if anyone can please help shed light on this topic.

<?php
//this is the path to my S3 resource
use PHPesources\aws\Aws\S3\S3Client;

$bucket = 'i put my bucket name here';
$keyname = 'yoyo';
// $filepath should be absolute path to a file on disk                      
$filepath = 'images/verified.png';

// Instantiate the client.
$s3 = S3Client::factory(array(
    'profile' => 'default',
));

//the contents of my credentials.ini file are
//[default]
//aws_access_key_id = myaccessidhere
//aws_secret_access_key = mysecretkeyhere



// Upload a file.
$result = $s3->putObject(array(
    'Bucket'       => $bucket,
    'Key'          => $keyname,
    'SourceFile'   => $filepath,
    'ACL'          => 'public-read',
    'StorageClass' => 'REDUCED_REDUNDANCY',
    )
));

echo $result['ObjectURL'];
echo 'done';
?>

Does anyone know why this code doesn't work at all? I would really really appreciate any help offerd, thank - you!