If you are a Comcast customer, you may not be getting emails from us (and others!). By default, Comcast hides email that it thinks are spam so you don’t even know you’ve received them without poking around, and automatically deletes them after a short period of time. An explanation of why this is happening and how to fix it is found in this article:
https://www.prrcomputers.com/blog/not-receiving-all-emails-at-comcast-how-to-fi/
You can also check these articles from Comcast, but you may have to contact them yourself if this does not solve the problem for you.
https://www.xfinity.com/support/articles/delete-contact-universal-address-book
https://forums.xfinity.com/t5/Email-Web-Browsing/Email-incorrectly-marked-as-spam/td-p/3303585#