No longer receiving UPSP Informed Delivery emails

I am signed up with the United States Postal Service Informed Delivery Service. I had been receiving their daily emails without issue until 2-3 months ago when they stopped coming. On the USPS site my settings are correct, and I've followed all the troubleshooting steps they provided. But I still am not receiving the daily email. I added the sender email to my contacts (USPSInformeddelivery@email.informeddelivery.usps.com) and that did not make a difference. I've also had this happen with another site twice, but they were able to fix the issue on their end. Any ideas on how I can fix this? I use the web interface to access my email.