IPN Validation Failed

[eluser]xerosis[/eluser]
Hi,
Suddenly out of the blue without touching my code as of today morning paypal is giving me IPN Vaidation Failed, I can not figure out why this happened suddenly it stopped working, the code below is what I get on the sandbox, very strange everything was working fine last night, can someone see what is the problem please:

[01/28/2013 6:08 PM] - FAIL: IPN Validation Failed.
IPN POST Vars from Paypal:
mc_gross=5.00, protection_eligibility=Ineligible, address_status=confirmed, payer_id=PQ55A3ADRGSNJ, tax=0.00, address_street=1 Main St, payment_date=06:08:10 Jan 28, 2013 PST, payment_status=Pending, charset=windows-1252, address_zip=95131, first_name=Hossein, address_country_code=US, address_name=Hossein Jalali, notify_version=3.7, custom=B2cCfVM3AyxQblo2AHZQJ1E2XGJQaVMTUTNUMA5gBXEJNQM8AmdWMQQ4CToAew5vBj9SPA,,, payer_status=verified, address_country=United States, address_city=San Jose, quantity=1, verify_sign=ARY-rEBAC4ofWw1n.x-HXDtmm6JAANMwGYx324h1G-EniCQY3QwTW2BD, payer_email=arnold_1358349356_per@edoramedia.com, txn_id=73B51487XR7203258, payment_type=instant, last_name=Jalali, address_state=CA, receiver_email=billing@edoramedia.com, pending_reason=unilateral, txn_type=web_accept, item_name=The Body Challenge, mc_currency=USD, item_number=, residence_country=US, test_ipn=1, handling_amount=0.00, transaction_subject=B2cCfVM3AyxQblo2AHZQJ1E2XGJQaVMTUTNUMA5gBXEJNQM8AmdWMQQ4CToAew5vBj9SPA,,, payment_gross=5.00, shipping=0.00, ipn_track_id=4fd5c037487b8,
IPN Response from Paypal Server:
HTTP/1.1 200 OK
Server: Apache
X-Frame-Options: SAMEORIGIN
Content-Type: text/html; charset=UTF-8
Date: Mon, 28 Jan 2013 14:08:13 GMT
Content-Length: 7
Connection: close
Set-Cookie: cwrClyrK4LoCV1fydGbAxiNL6iG=uLYVcSvP_xknbquLYS3ns-w0g9-tv5hBZasRWdcJUdZDvJBjt_vrpq1cVWX8gbSYGM7edM2AzHQgKyMCWVNdlGSl7TYqcqhpC7gvGvKbuDAkaF9Nr-u9qZ1ixF4|EtaWhAeTEKXqBpgHSxGo5VymYkIwU2LerFv_hqBvnQdPOa6Ue-vHYPPCOvf70mqKZA1cx0|j9ihJtYiQP1tBFLSXNQr92hZ3uiziTHhuo1CV66g_hy-5JwdqwRbNNZA-jdzXVM0Czlue0|1359382093; domain=.paypal.com; path=/; HttpOnly
Set-Cookie: cookie_check=yes; expires=Thu, 26-Jan-2023 14:08:13 GMT; domain=.paypal.com; path=/; HttpOnly
Set-Cookie: navcmd=_notify-validate; domain=.paypal.com; path=/; HttpOnly
Set-Cookie: navlns=0.0; expires=Sun, 23-Jan-2033 14:08:13 GMT; domain=.paypal.com; path=/; HttpOnly
Set-Cookie: aksession=1359382393~id=cookielPmmjSh/wB8M4j7I1HrF9hxmh87SCjUxNHoiW0Vh3wvVVp2U8kaEgffYq49di44z+qzZ5ABckjMicxhH/M2KTKsR3Bh1bxmgYnrKv3EU0j9FZnYMgTf85pI785pZq6wQ; expires=Mon, 28-Jan-2013 14:13:13 GMT; path=/; domain=.paypal.com