Zoho crm API sometimes returns error - api

Question

I'm trying to searchRecord using the Zoho CRM API and I sometimes get the following error:
Array ( [response] => Array ( [error] => Array ( [message] => Unable
to process your request. Please verify whether you have entered proper
method name,parameter and parameter values. [code] => 4600 ) [uri] =>
/crm/private/json/Contacts/searchRecords ) )
My problem is that sometimes everything works fine and sometimes I get this error
define("TARGETURL", "https://crm.zoho.com/crm/private/json/Contacts/searchRecords");
$parameter = array(
'scope' => 'crmapi',
'authtoken' => AUTHTOKEN,
'selectColumns' => 'All',
'criteria' => '(Account Name:'.$accountName.')',
'fromIndex' => $fromIndex,
'toIndex' => $toIndex
);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, TARGETURL);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_TIMEOUT, 30);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $parameter);
$result = curl_exec($ch);
curl_close($ch);

Answer 1

Try search field with double quotation mark, following is script to search email from lead module.
$xmlData = "(Email:$email)";
$ch = curl_init('https://crm.zoho.com/crm/private/xml/Leads/searchRecords');
curl_setopt($ch, CURLOPT_VERBOSE, 1); //standard i/o streams
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); // Turn off the server and peer verification
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); //Set to return data to string ($response)
curl_setopt($ch, CURLOPT_POST, 1); //Regular post
$authtoken = "********************************";
$query = "authtoken=" . $authtoken . "&scope=crmapi&criteria=" . $xmlData;
curl_setopt($ch, CURLOPT_POSTFIELDS, $query); // Set the request as a POST FIELD for curl.
$response = curl_exec($ch);
curl_close($ch);