Does Charity Hub paypal plug in use IPN?

I have opened a Member ticket on this but have not heard back in a few days. The component was working and then the Paypal transaction code stopped being recorded and we started getting these emails from Paypal


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

autismontheseas.com/index.php?option=com...ayment_method=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.

Should we use Paypal's IPN? We currently DO NOT have IPN enabled. Should we?
Paypal instructions say to create a listener. Is that already built in to the plugin? Do I just need to enable it?

Hi Ellen.
Thank you for using our product.
I'm very sorry for reply late, can my colleague had read them and still doesn't find the solution for your issue.
Please give me some time. Today I will check it for you,
Thank you so much for empathy