We have a family email domain for my extended family, administered by a few retired but very tech-savvy relatives (both had long IT careers) and it’s roughly 50:50 whether a message sent to everyone@ lastname.com will actually show up in people’s inboxes or not. It’s probably 75:25 that a reply all to that list will show up, but modern email is a dumpster fire.

Is this using some cloud-based email host where you don't have any control over the spam filter? Otherwise, whitelisting (verified) senders from your own dowmain should be very much possible.

E-Mail isn't some magic that randomly drops mails. Mail servers are even resilient against network problems and will retry dilevery MANY times. What you are describing is NOT normal and would make using it for business basically impossible, which is not the case since email is still the primary b2b communication method for many companies.

I uses the business version of Office 365 for e-mail. It works well. I never have a problem with e-mails not being delivered or going into a SPAM folder. I am not saying your family did anything wrong. What I am saying is e-mail works well for some people.

Yeah, unfortunately that seems to be the best way to handle this kind of thing but unfortunately that costs $6/person/month so our ~50 person casual email list for organizing fantasy football and family reunions would cost almost $4k/year.