[Plugin: Contact Form 7] Plugin not working with Gmail serverx

Hi,
I am new to wordpress and your plugin so appologies if I am being a noob here.

I have just installed my first ever theme and wordpress website and trying to get your plugin to email me when a user goes on our contact page at https://www.manishkumar.co.uk/contacts/

The issue is that it works fine with dumb / fake email address but always gets into trouble with real email addresses – I have tried with gmail & hotmail and it always fails.

If I try with [email protected] or anything fake then it works.

I have noticed below in the email header which may give you some clues.

Received: by 10.194.11.98 with SMTP id p2csp3413wjb;
        Fri, 4 May 2012 17:09:33 -0700 (PDT)
Received: by 10.60.10.231 with SMTP id l7mr1368911oeb.4.1336176573249;
        Fri, 04 May 2012 17:09:33 -0700 (PDT)
Return-Path: <[email protected]>
Received: from n1nlshrout02.shr.prod.ams1.secureserver.net (n1nlshrout02.shr.prod.ams1.secureserver.net. [188.121.43.194])
        by mx.google.com with SMTP id tc6si5970799obc.12.2012.05.04.17.09.32;
        Fri, 04 May 2012 17:09:32 -0700 (PDT)
Received-SPF: neutral (google.com: 188.121.43.194 is neither permitted nor denied by best guess record for domain of [email protected]) client-ip=188.121.43.194;
Authentication-Results: mx.google.com; spf=neutral (google.com: 188.121.43.194 is neither permitted nor denied by best guess record for domain of [email protected]) [email protected]
Received: (qmail 24477 invoked from network); 5 May 2012 00:09:31 -0000
Received: from unknown (HELO www.manishkumar.co.uk) ([188.121.41.107])
          (envelope-sender <[email protected]>)
          by n1nlshrout02.shr.prod.ams1.secureserver.net (qmail-ldap-1.03) with SMTP
          for <[email protected]>; 5 May 2012 00:09:31 -0000
Date: Sat, 5 May 2012 00:09:31 +0000
Return-Path: [email protected]
To: [email protected]
From: Manis <[email protected]>
Subject: Contact Us Email - ManishKumar.co.uk
Message-ID: <[email protected]>
X-Priority: 3
X-Mailer: PHPMailer 5.1 (phpmailer.sourceforge.net)
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain; charset="UTF-8"

My domains email is hosted under Google mail app with email SPF and DKIM enabled. I didnt find a place in your settings to add these or I would have added these myself.

Please help me as I want to get this site running asap as I need it for my MBA admission.

Thanks,
Manish

https://www.ads-software.com/extend/plugins/contact-form-7/