wsdl/soap failed to load external entity

I am using ASIHTTPRequest in my iOS app. I am calling a wsdl/Soap web services like this :

NSData开发者_高级运维 *xmlData =  // I construct the soap message witk soapui

NSURL *url = [NSURL URLWithString:@"https:myUrlWSDL"];
self.currentRequest = [ASIFormDataRequest requestWithURL:url];
[self.currentRequest appendPostData:xmlData];
[self.currentRequest setDelegate:self];
[self.currentRequest startAsynchronous];

but the server return to me this error :

<?xml version="1.0" encoding="UTF-8"?> <SOAP-ENV:Envelope xmlns:SOAP-ENV="schemas.xmlsoap.org/soap/envelope/…: Parsing WSDL: Couldn't load from 'http://...?wsdl' : failed to load external entity "http://...?wsdl"

it is a probleme with ssl ?? thanks for your answers