diff --git a/README.md b/README.md
index debf755..f6faeb6 100644
--- a/README.md
+++ b/README.md
@@ -56,7 +56,7 @@ try {
     }
 } catch (RonMelkhior\CoinpaymentsIPN\Exceptions\InvalidRequestException $e) {
     // The IPN data was not valid to begin with (missing data, invalid IPN method).
-} catch (RonMelkhior\CoinpaymentsIPN\Exceptions\InvalidDataException $e) {
+} catch (RonMelkhior\CoinpaymentsIPN\Exceptions\InsufficientDataException $e) {
     // Sufficient data provided, but either the merchant ID or the IPN secret didn't match.
 } catch (RonMelkhior\CoinpaymentsIPN\Exceptions\FailedPaymentException $e) {
     // IPN worked, but the payment has failed (PayPal refund/cancelled/timed out).
diff --git a/src/RonMelkhior/CoinpaymentsIPN/IPN.php b/src/RonMelkhior/CoinpaymentsIPN/IPN.php
index c7ef155..1550956 100644
--- a/src/RonMelkhior/CoinpaymentsIPN/IPN.php
+++ b/src/RonMelkhior/CoinpaymentsIPN/IPN.php
@@ -4,7 +4,7 @@
 
 use RonMelkhior\CoinpaymentsIPN\Initialize;
 use RonMelkhior\CoinpaymentsIPN\Exceptions\InvalidRequestException;
-use RonMelkhior\CoinpaymentsIPN\Exceptions\InvalidDataException;
+use RonMelkhior\CoinpaymentsIPN\Exceptions\InsufficientDataException;
 use RonMelkhior\CoinpaymentsIPN\Exceptions\FailedPaymentException;
 
 class IPN
@@ -29,11 +29,11 @@ public function validate(array $post_data, array $server_data)
         }
 
         if ($server_data['PHP_AUTH_USER'] !== $this->merchant_id) {
-            throw new InvalidDataException("Invalid merchant ID provided.");
+            throw new InsufficientDataException("Invalid merchant ID provided.");
         }
 
         if ($server_data['PHP_AUTH_PW'] !== $this->ipn_secret) {
-            throw new InvalidDataException("Invalid IPN secret provided.");
+            throw new InsufficientDataException("Invalid IPN secret provided.");
         }
 
         $order_status = $post_data['status'];