eMails from a No-Reply Account Stopped

I have several devices at my home that are capable of sending messages when the devices are triggered. The system allows text, email and app notifications. After working flawlessly for months, I stopped receiving emails from from the no-reply address used for the email notifications. The app and text notifications are still working fine. I contacted their customer support, which uses the same domain as the no-reply address and they gave me several suggestions to make sure my Yahoo mail account wasn't the problem. I've checked everything I can think of including blocked email addresses and domains (both of those lists are empty). To reiterate, the no-reply and tech support domains are the same. However, I'm not getting the no-reply emails while the tech support emails come through fine. To get around the problem, I created a Gmail account for the sole purpose of automatically forwarding these email to my Yahoo account. When these emails arrive in my Yahoo account, they appear to come from the no-reply account (including the no-reply domain). I made no changes to my filters and they are filtered exactly as they were when the no-reply account was working properly. They ended up elevating this issue to their 2nd tier tech support. They finally came back and said they checked their email system and found no problems. Then they stated "if you are not receiving emails from our system, it is likely that they are being blocked by your email service or filtered out by your email operator. We recommend reaching out to your email provider's support team to resolve this issue." I'm not sure this is the right way to reach out for help, but, after searching the internet for how to get help with Yahoo email, this is where I ended up. For more clarification, my email domain is sbcglobal.net and the no-reply domain is yosmart.com.