IPN was not sent, and the handshake was not verified. Please review your information.

Question

I am working with Expresscheckout on Paypal, For single time Users payment integration. Working flow 1st create token and user redirect to paypal page and success to my return url page. 1.SetExpressCheckout 2. DoExpressCheckoutPayment

My Problem: 1.Now i need to set ipn for this payment system. 2.My notify url is not working on simulator.It gives error(IPN was not sent, and the handshake was not verified. Please review your information.) https://developer.paypal.com/developer/ipnSimulator/

I need some help for this is not set on my side. Please help me out on this.

Thank you in advance.

Answer 1

The handshake error is most likely to occur when your server/keystore config is non-compliant with the upgraded PayPal SSL encryption algorithms.

IPN simulator will connect againest the PayPal Sandbox environment, which has been upgraded with Versign G5 root cert / SHA-2 encryption algorithms (btw this is an industry standard as supposed to be everywhere in 2016). Once your IPN host failed to meet the compliance, the SSL connnection will error out with handshake problems.

Simply check your server by running a connection script against the PayPal sandbox endpoint like this:

openssl s_client -connect api-3t.sandbox.paypal.com:443 -showcerts -CApath /etc/ssl/certs/  

If you were not getting an Verify return code: 0 (ok), you would probably have to check the cert/SHA-2 compatibility, following the general instructions that PayPal has published here:

2015-2016 SSL Certificate Change Microsite

Answer 2

I was having the same issue. A workaround to test IPN messages would be to actually setup IPN notification URL on your Sandbox business account and test it from there.

• Login to https://sandbox.paypal.com with your sandbox business account ([email protected])
• Navigate to your Account Settings page
• Website Payments
• Update Instant payment notifications
• set your notification URL there.

Make sure, your IPN listener is not behind firewall and is directly accessible from outside world.