Help me, GAE/PHP Inexplicable behavior google cloud storage' s response

[satoshi tagomori]

upload image response returned status code 200 in code and log 

but client recived 500 error

help me.

createuploadurl.php

....

$upload_url = CloudStorageTools::createUploadUrl('/api/upload/upload', $options);

....

upload.php

....

....

header('Content-Type: application/json; charset=utf-8');

echo json_encode($result, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE);

syslog(LOG_DEBUG,"success.");

log is success

[George (Cloud Platform Support)]

Hello Satoshi, 

You must start uploading to this URL within 10 minutes of its creation. Have you followed the relevant documentation page at "Allowing Users to Upload Files" with all the steps indicated there? How did you get the 500 error, exactly? 

More detail on your code and the exact steps you undertook is needed to properly organize an investigation. Whatever information you deem relevant is likely to help as well.