curl_exec not working inside a loop - php

Question

I have a class with the function below. When I call that function directly it works, but if I call that function inside the loop I got an error: Cannot connect to host. Can somebody help me? :) Thanks in advance.
public function exportProfile($xml) {
$_myRequest = curl_init("https://www.example.com/postProfile");
curl_setopt($_myRequest, CURLOPT_POST, 1);
curl_setopt($_myRequest, CURLOPT_USERPWD, "testUser:testPassword");
curl_setopt($_myRequest, CURLOPT_HTTPHEADER, Array("Content-Type: application/xml"));
curl_setopt($_myRequest, CURLOPT_POSTFIELDS,$xml );
curl_setopt($_myRequest, CURLOPT_RETURNTRANSFER, 1);
// do request, the response text is available in $_response
$_response = curl_exec($_myRequest);
$err = curl_error($_myRequest) ;
echo $err;
$_statusCode = curl_getinfo($_myRequest, CURLINFO_HTTP_CODE);
// close cURL resource, and free up system resources
curl_close($_myRequest);
return simplexml_load_string($_response);
}

Answer 1

I can't reproduce that problem with a simple example. Your example code seems to have a syntax error in CURLOPT_USERPWD, but I assume that is not related.
It sounds quite likely that there could there be rate limiting on the site you are querying, i.e. when you hit them a few times in a row they lock you out.
Perhaps you could debug by trying to run the query multiple times outside of the loop, i.e. calling it 1/2/3 times manually.