GuzzleHttp Undefined offset: 1

Hi Guys

I am trying to integrate to a payment gateway and send sms'es from my application using GuzzleHttp:

i get the error in the tile and suspect is how i am passing the authentication as required by the API

Authentication requirement:

When using an API token, the value to be encoded will be <token-id>:<token-secret>. These values before Base64 encoding look something like this

BBDE1B476E03498AA768F66A286AABDC-01-B:9jSbVDK20!MXdfRGiIIFu#ffUE8*S

My API call:

        public function initiateSmsGuzzle($employeeMobile, $message)
                {
                  $client=new Client([
                    'headers'=>['content-type'=>'application/json','Accept'=>'application/json'],
                    ]);
                    
                    $ID=base64_encode('******_ID');
                    $KEY=base64_encode('******_KEY');

                     $response = $client->request('POST','https://api.bulksms.com/v1', [
                        'auth'=>[$ID.':'.$KEY],
                        'form_params' => [
                        
                        'message' => $message,
                        
                        'mobiles' => $employeeMobile,
                        ],
                ]);


        $response = json_decode($response->getBody(), true);
    }
    

The error above refers to this part of the Guzzle file:

laravel/vendor/guzzlehttp/guzzle/src/Client.php line 354

and that part contains this:

      if (!empty($options['auth']) && is_array($options['auth'])) {
            $value = $options['auth'];
            $type = isset($value[2]) ? strtolower($value[2]) : 'basic';
            switch ($type) {
                case 'basic':
                    // Ensure that we don't have the header in different case and set the new value.
                    $modify['set_headers'] = Psr7\_caseless_remove(['Authorization'], $modify['set_headers']);
                    $modify['set_headers']['Authorization'] = 'Basic '
                        . base64_encode("$value[0]:$value[1]");  //THIS IS LINE 354
                    break;
                case 'digest':
                    // @todo: Do not rely on curl
                    $options['curl'][CURLOPT_HTTPAUTH] = CURLAUTH_DIGEST;
                    $options['curl'][CURLOPT_USERPWD] = "$value[0]:$value[1]";
                    break;
                case 'ntlm':
                    $options['curl'][CURLOPT_HTTPAUTH] = CURLAUTH_NTLM;
                    $options['curl'][CURLOPT_USERPWD] = "$value[0]:$value[1]";
                    break;
            }
        }