diff --git a/src/Operations/AOperation.php b/src/Operations/AOperation.php
index f82d264..5f8e60c 100644
--- a/src/Operations/AOperation.php
+++ b/src/Operations/AOperation.php
@@ -43,17 +43,26 @@ protected function request($path, array $options = array())
 
         $response     = curl_exec($curl);
         $requestState = curl_getinfo($curl);
+        $message      = '';
 
         if ($requestState['http_code'] != 200 && $requestState['http_code'] != 204) {
             switch ($requestState['http_code']) {
                 case 400:
-                    throw new MailosaurException('Request had one or more invalid parameters.', 'invalid_request', $requestState['http_code'], $response);
+                    try {
+                        $json = json_decode($response);
+                        foreach ($json->{'errors'} as &$err) {
+                            $message .= '(' . $err->field . ') ' . $err->detail[0]->description . '\r\n';
+                        }
+                    } catch (Exception $ex) {
+                        $message = 'Request had one or more invalid parameters.';
+                    }
+                    throw new MailosaurException($message, 'invalid_request', $requestState['http_code'], $response);
                 case 401:
                     throw new MailosaurException('Authentication failed, check your API key.', 'authentication_error', $requestState['http_code'], $response);
                 case 403:
                     throw new MailosaurException('Insufficient permission to perform that task.', 'permission_error', $requestState['http_code'], $response);
                 case 404:
-                    throw new MailosaurException('Request did not find any matching resources.', 'invalid_request', $requestState['http_code'], $response);
+                    throw new MailosaurException('Not found, check input parameters.', 'invalid_request', $requestState['http_code'], $response);
                 default:
                     throw new MailosaurException('An API error occurred, see httpResponse for further information.', 'api_error', $requestState['http_code'], $response);
             }
@@ -61,4 +70,4 @@ protected function request($path, array $options = array())
 
         return $response;
     }
-}
\ No newline at end of file
+}
diff --git a/tests/ErrorsTests.php b/tests/ErrorsTests.php
new file mode 100644
index 0000000..51ccf02
--- /dev/null
+++ b/tests/ErrorsTests.php
@@ -0,0 +1,42 @@
+<?php
+
+namespace Mailosaur_Test;
+
+
+use Mailosaur\MailosaurClient;
+use Mailosaur\Models\ServerCreateOptions;
+use Mailosaur\Models\MailosaurException;
+
+class ErrorsTests extends \PHPUnit\Framework\TestCase
+{
+    public function testUnauthorized()
+    {
+        try {
+            $client = new MailosaurClient('invalid_key');
+            $client->servers->all();
+        } catch(MailosaurException $e) {
+            $this->assertEquals('Authentication failed, check your API key.', $e->getMessage());
+        }
+    }
+
+    public function testNotFound()
+    {
+        try {
+            $client = new MailosaurClient(getenv('MAILOSAUR_API_KEY'));
+            $client->servers->get('not_found');
+        } catch(MailosaurException $e) {
+            $this->assertEquals('Not found, check input parameters.', $e->getMessage());
+        }
+    }
+
+    public function testBadRequest()
+    {
+        try {
+            $client = new MailosaurClient(getenv('MAILOSAUR_API_KEY'));
+            $options = new ServerCreateOptions();
+            $client->servers->create($options);
+        } catch(MailosaurException $e) {
+            $this->assertEquals('(name) Please provide a name for your server\r\n', $e->getMessage());
+        }
+    }
+}
diff --git a/tests/ServersTests.php b/tests/ServersTests.php
index 74a2c02..35a557f 100644
--- a/tests/ServersTests.php
+++ b/tests/ServersTests.php
@@ -85,10 +85,10 @@ public function testFailedCreate()
             $options = new ServerCreateOptions();
             self::$client->servers->create($options);
         } catch(MailosaurException $e) {
-            $this->assertEquals('Request had one or more invalid parameters.', $e->getMessage());
+            $this->assertEquals('(name) Please provide a name for your server\r\n', $e->getMessage());
             $this->assertEquals('invalid_request', $e->errorType);
             $this->assertEquals(400, $e->httpStatusCode);
             $this->assertStringContainsString('{"type":', $e->httpResponseBody);
         }
     }
-}
\ No newline at end of file
+}