Payrexx Select2Pay - Create a paylink - PHP Integration Curl does not work with spaces

The example in the current documentation (2022-06-15) does not work with strings with spaces.

https://developers.payrexx.com/reference/create-a-paylink

It returns the error message: "An error occurred: The API secret is not correct."

Here is a working example for PHP Curl:

    $data = [
      'title' => 'foo',
      'description' => 'a funny description',
      'referenceId' => 1234,
      'purpose' => 'nopurpose',
      'amount' => 666,
      'currency' => 'EUR',
      ];

    $signature = base64_encode(hash_hmac('sha256', http_build_query($data), 'xxxxxxxxxxxxxxxxx', true));
    $data['ApiSignature'] = $signature;
    
    // Now build data / query again with the api signature
    $data['ApiSignature'] = $signature;
    $query = http_build_query($data);

    $curl = curl_init();

    curl_setopt_array($curl, [
      CURLOPT_URL => 'https://api.payrexx.com/v1.0/Invoice/?instance=xxx',
      CURLOPT_RETURNTRANSFER => true,
      CURLOPT_ENCODING => '',
      CURLOPT_MAXREDIRS => 10,
      CURLOPT_TIMEOUT => 30,
      CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
      CURLOPT_CUSTOMREQUEST => 'POST',
      CURLOPT_POSTFIELDS => $data,
      CURLOPT_HTTPHEADER => [
        'Accept: application/json',
        'Content-Type: application/x-www-form-urlencoded'
      ],
    ]);

    $response = curl_exec($curl);