diff --git a/Opencart_V1.5.x/upload/catalog/controller/payment/paytm.php b/Opencart_V1.5.x/upload/catalog/controller/payment/paytm.php
index 38f48aa..147db82 100755
--- a/Opencart_V1.5.x/upload/catalog/controller/payment/paytm.php
+++ b/Opencart_V1.5.x/upload/catalog/controller/payment/paytm.php
@@ -90,7 +90,7 @@ private function blinkCheckoutSend($paramData = array()){
 	* get Default callback url
 	*/
 	private function getCallbackUrl(){
-		if(!empty(PaytmConstants::CUSTOM_CALLBACK_URL)){
+		if(PaytmConstants::CUSTOM_CALLBACK_URL!=''){
 			return PaytmConstants::CUSTOM_CALLBACK_URL;
 		}else{
 			return $this->url->link('payment/paytm/callback');
@@ -339,4 +339,4 @@ public function curltest(){
 	}
 
 }
-?>
\ No newline at end of file
+?>