How to generate a signature for zoom in PHP

signature.php

/**
* Generate signature for ZoomMtg JSSDK.
*
* @param string $api_key You REST API Key
* @param string $api_secret You REST API Secret
* @param int $meeting_number The meeting number you are creating the signature for
* @param int $role Role that this signature is for; 0 for participant, 1 for host
* 
* @return string Returns the signature string
*
*/

function generate_signature ( $api_key, $api_sercet, $meeting_number, $role){

	$time = time() * 1000; //time in milliseconds (or close enough)
	
	$data = base64_encode($api_key . $meeting_number . $time . $role);
	
	$hash = hash_hmac('sha256', $data, $api_sercet, true);
	
	$_sig = $api_key . "." . $meeting_number . "." . $time . "." . $role . "." . base64_encode($hash);
	
	//return signature, url safe base64 encoded
	return rtrim(strtr(base64_encode($_sig), '+/', '-_'), '=');
}

but it is generating wrong signature