In endpoint.php on line 109 you can see the following code:
php $headersStr = $contentAsObject["headers"];
This key though "headers" doesn't exists. When I use the fineuploader library only "expiration" and "conditions" exists.
Somehow when I use this library for testing reasons, this doesn't trigger any errors and $headersStr will be null. But in a different implementation on production it triggers Undefined index: headers.
Can we fix this by checking the array for the header something like:
$headerStr = '';
if (isset($contentAsObject["headers"]) {
$headerStr = $contentAsObject["headers"];
}