We have recently improved our error reporting for sellers using our optional custom/3rd-party Integration feature:
The Integration feature itself has not changed, so if you're suddenly receiving new error reports now, that indicates you have an incorrect Integration URL setting that never worked but previously wasn't getting reported due to the type of error, rather than something that has stopped working just now. This would not have affected our ability to process orders for you, because this optional feature only sends the order data to your server for additional custom needs after we're already done processing the order.
In your particular case, it appears you have entered an invalid Common Notification URL in your Seller Admin > Account Preferences, so you can just delete that setting. This is unrelated to the Sale Notification emails we send to your E-junkie Login Email, which you would continue receiving as before.