Errors in Order Processing

I have seen this issue and it’s been resolved, but I don’t see how to fix it. My orders are processing and being charged, but I am not getting the notifications. I also have to go in and manually mark them as processed.

I have everything set up properly in WooCommerce. Not sure what else to do.

Thank you!

http://www.kateyounger.com

https://wordpress.org/plugins/authorizenet-payment-gateway-for-woocommerce/