Conflicting with the PayPal IPN

I got an email from paypay to say:

“Please check your server that handles PayPal Instant Payment Notifications (IPN). Instant Payment Notifications sent to the following URL(s) are failing:

https://sunshineandgreen.co.uk/wc-api/WC_Gateway_Paypal/

If you do not recognize this URL, you may be using a service provider that is using IPN on your behalf. Please contact your service provider with the above information. If this problem continues, IPNs may be disabled for your account.

Thank you for your prompt attention to this issue.”

Contacted my hosting company and they said:

“I do believe that the error provided above is causing the issue:

sunshineandgreen.co.uk [Tue Oct 02 12:56:55 2018] [error] [client 185.151.28.62:50456] #5 /hom in /home/sites/3b/e/e156cb6e23/public_html/wp-content/plugins/xa-woocommerce-subscriptions/includes/hf-includes/class-hf-paypal-standard-ipn-handler.php on line 222

I would recommend speaking with the plugin developer as you can see that this is conflicting with the PayPal IPN ”

Any ideas? Please help.

The page I need help with: [log in to see the link]