Problem with api v2 Fetching http headers

[roms08]

Hello,

i have a problem with soap api V2 from magento. 

My system was working since 1 year and it doesnt work since 4 days and i don't know why.

I got this error many times : 

Warning: SoapFault : HTTP : Error Fetching http headers

I check on the web, try to ajust default_socket_timeout but it doesn't work. 

Magento is on 1.9.2.4 and i install recently shopping flux module to sell on amazon marketplace. 

My system is on Linux 8.5 with apache2

I use this sample code to do tests (i run this code through command line): 

$mageUrl    = 'http://mydomain/index.php/api/v2_soap?wsdl=1';
$mageUser   = 'myuser';
$mageApiKey = 'mypassword';

//try{
$soap = new SoapClient($mageUrl);
$sessionID = $soap->login($mageUser, $mageApiKey);

$params = array('complex_filter'=>
    array(
        array('key'=>'created_at','value'=>array('key' =>'from','value' => '2016-07-18 00:00:00'))
    )
);

$orderinfo = $soap->salesOrderList($sessionID,$params);
var_dump($orderinfo);

My test works 3 or 4 times, and sometimes i got this Error Fetching http headers and i don't know why.

Someone can help me to find a solution please ?