Updated README

README

@@ -16,4 +16,30 @@ Quick Examples
      $sms = new NexmoMessage('account_key', 'account_secret');
      if ($sms->inboundText()) {
          $sms->reply('You said: ' . $sms->text);
-     }
+     }
+
+
+
+
+
+
+Most Frequent Issues
+--------------------
+
+ Sending a message returns false.
+
+    This is usually due to your webserver unable to send a request to
+    Nexmo. Make sure the following are met:
+
+    1) Either CURL is enabled for your PHP installation or the PHP
+       option 'allow_url_fopen' is set to 1 (default).
+
+    2) You have no firewalls blocking access to rest.nexmo.com/sms/json
+       on port 443.
+
+
+
+ Your message appears to have been sent but you do not recieve it.
+
+ 	Run the example.php file included. This will show any errors that
+ 	are returned from Nexmo.