SoapFault异常：[Client]看起来我们没有XML文档

I've hit an issue with the PHP SoapClient.

Here is the code:

$obj = new SoapClient(WEBSERVICE_ADDRESS,array('trace' => 1,'encoding'=>'utf-8', 'exceptions' => 0)); 

$res_obj = ($obj->searchTextBySummaryAndDescription($params));

$res_obj is a object. It includes a bug list. Every bug has details such as Bugdescription. The issue is that one of the Bug Description has a special character "←", so I see an error as per my question's title when I try to run eg: print $res_obj;

try adding

error_reporting( 0 ) ;

to the top of the page.

I got this:

Fatal error: Uncaught SoapFault exception: [Client] looks like we got no XML document...

and, I change in php.ini file row

;always_populate_raw_post_data = -1

with this:

always_populate_raw_post_data = -1

e.g. without ;