diff --git a/src/executors/credit/DeferredCreditExec.php b/src/executors/credit/DeferredCreditExec.php
index 425efcd..c737871 100644
--- a/src/executors/credit/DeferredCreditExec.php
+++ b/src/executors/credit/DeferredCreditExec.php
@@ -37,7 +37,7 @@ static function getSuccessResponse($responseHeader) {
     static function deferredCredit(DeferredCreditRequest $request, PhonePeClientConfig $phonePeClientConfig) {
         $url = $phonePeClientConfig->mercuryBaseUrl . '/v1/credit/deferred';
         $args = array($request->merchantId, $request->transactionId, $request->amount, $request->header->salt->key, $request->header->salt->index);
-        $headers = 'Content-type:application/json ' . 'X-VERIFY:' . ChecksumGenerator::checkSumGenerate($args) . 'X-CALLBACK-URL:' . $request->header->callBackUri;
+        $headers = 'Content-type:application/json ' . 'X-VERIFY:' . ChecksumGenerator::checkSumGenerate($args) . ' X-CALLBACK-URL:' . $request->header->callBackUri;
         $responseArray = RequestGenerator::postRequest($url, $request, $headers);
         if ($responseArray[1]['http_code'] != 302) {
             $response = json_decode($responseArray[0]);
diff --git a/src/executors/credit/RegularCreditExec.php b/src/executors/credit/RegularCreditExec.php
index 6bb565e..3c88af9 100644
--- a/src/executors/credit/RegularCreditExec.php
+++ b/src/executors/credit/RegularCreditExec.php
@@ -39,7 +39,7 @@ static function getSuccessResponse($responseHeader) {
     static function regularCredit(RegularCreditRequest $request, PhonePeClientConfig $phonePeClientConfig) {
         $url = $phonePeClientConfig->mercuryBaseUrl . '/v1/credit/';
         $args = array($request->merchantId, $request->transactionId, $request->amount, $request->header->salt->key, $request->header->salt->index);
-        $headers = 'Content-type:application/json ' . 'X-VERIFY:' . ChecksumGenerator::checkSumGenerate($args) . 'X-CALLBACK-URL:' . $request->header->callBackUri;
+        $headers = 'Content-type:application/json ' . 'X-VERIFY:' . ChecksumGenerator::checkSumGenerate($args) . ' X-CALLBACK-URL:' . $request->header->callBackUri;
         $responseArray = RequestGenerator::postRequest($url, $request, $headers);
         if ($responseArray[1]['http_code'] != 302) {
             $response = json_decode($responseArray[0]);
diff --git a/src/executors/debit/RegularDebitExec.php b/src/executors/debit/RegularDebitExec.php
index 6c85079..68b7027 100644
--- a/src/executors/debit/RegularDebitExec.php
+++ b/src/executors/debit/RegularDebitExec.php
@@ -41,7 +41,7 @@ static function regularDebit(RegularDebitRequest $request, PhonePeClientConfig $
     {
         $url = $phonePeClientConfig->mercuryBaseUrl . '/v1/debit/';
         $args = array($request->merchantId, $request->transactionId, $request->amount, $request->header->salt->key, $request->header->salt->index);
-        $headers = 'Content-type:application/json ' . 'X-VERIFY:' . ChecksumGenerator::checkSumGenerate($args) . 'X-CALLBACK-URL:' . $request->header->callBackUri;
+        $headers = 'Content-type:application/json ' . 'X-VERIFY:' . ChecksumGenerator::checkSumGenerate($args) . ' X-CALLBACK-URL:' . $request->header->callBackUri;
         $responseArray = RequestGenerator::postRequest($url, $request, $headers);
         if ($responseArray[1]['http_code'] != 302) {
             $response = json_decode($responseArray[0]);