Access token corrupted in SMS API

Hi Ringcentral,

I use Ring central SMS API in PHP. I got message "Access token corrupted" when I try to send SMS. I searched for this but not found any solution.

My application is in under development mode.

Here is my code:

function send_sms(){
  
  $credential = get_access_token();
  $access_token = refresh_access_token($credential['refresh_token']);  
  
  if(isset($access_token['error']) && $access_token['error']!=''){
    echo $access_token['error_description'];
  }
  else{
    
    $url = "https://platform.devtest.ringcentral.com/restapi/v1.0/account/177248004/extension/101/sms";    
    $header = array("Accept: application/json;","Authorization: Bearer ".$access_token['access_token'].";","Content Type: application/json;");
    $sms_data =  json_encode(array("from"=>array("phoneNumber"=> RC_FROM_PHONE_NUMBER),"to"=>array(array("phoneNumber"=> $_POST['phone'])),"text"=>trim($_POST['message'])));
     
    $objCCurl = new CCurl();
    $data = $objCCurl->curl_request($url,'POST',$sms_data,$header,false,false);
    
    if(isset($data['errorCode']) && $data['errorCode']!=''){
      
      $err = $data['errorCode'];
      if(isset($data['message']) && $data['message']!=''){
        $err .= ' - '.$data['message'];
      }
    }    
    else{
      //success
    }
   
    
  }
  
  
}

OUTPUT :

{ "errorCode" : "TokenInvalid", "message" : "Access token corrupted", "errors" : [ { "errorCode" : "OAU-129", "message" : "Access token corrupted" } ] }


Please let me know how to resolve this error.

Thanks in advance.