CI throws 401 on a CURL request

I have created a simple API to check the newest version of software.
If I call this endpoint directly in the browser everything works.
But when I try to get the same contents via curl, a 401 is thrown....
This is the request:

PHP Code:

$handler = curl_init($url);
curl_setopt($handler, CURLOPT_RETURNTRANSFER, true);
curl_setopt($handler, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($handler, CURLOPT_HTTPHEADER, $headers);
curl_setopt($handler, CURLOPT_POST, 1);
curl_setopt($handler, CURLOPT_POSTFIELDS, $postFields);
$apiOutput = curl_exec($handler); 


And this is the (simplified) endpoint:

PHP Code:

    

public function versionInfo()
    {
        $output = ['version' => 2];
        return $this->response->setJSON($output);

    } 


READ:

debugbar - HTTP 401 Unauthorized Access Error

What did you Try? What did you Get? What did you Expect?

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