After a seemingly endless battle on this topic last year surrounding the Pandora AP Preview, I finally got to someone who explained to me what was wrong and why I wasn't getting the communications.
It seems to all go back to an issue Disney had with sending marketing messages to parties that did not want, and/or should not receive them back in the early 2000's. It gets a little convoluted to explain here but if back in the early 2000's, you for any reason told Disney not to send you marketing messages even once, your email address was put on a block-list from their outbound email systems and no matter what anyone does, the message will never get delivered to that email address. Their systems will show the message was sent, but it will be dumped downstream and never transmitted by the block-list, and nobody can see that is what happened. Many people have commented that Disney asks them to 'get a new email address' and see if that fixes it. What they are trying to do is have you switch to a different email address that is not on the block-list because they have no ability to remove you from that list.
When I went through it with the Pandora preview last year I had reached the end of my patience and was determined to get it resolved (think dog with a rope who is not letting go). I did not relent for weeks and would be on the phone with people sending emails from the marketing system that were never received, but a message from a
Guest.Relations@disneyworld.com address come right through. They couldn't figure it out so they started engaging more and more people until I got to some who finally knew why it happens. It's the block-list from the early 2000's. The frustrating part of all of this is that only certain types of communications get blocked which makes it even harder for them to troubleshoot. I get emails about Fastpass, or Dining Reservations with no issues at all.
Last year when the Pandora mess happened they finally agreed to add a second email to my account. I have a personalized domain and email and was unwilling to change email due to their systems problems. Now when the messages for Passholder related stuff (like the Toy Story Post-Preview & VIPassholder) go out they are sent to both email addresses (both show up in the To Field) but they are only received by me on the new address we added last year. To my knowledge, I'm now getting all of the communications for Passholders that I had not received in well over a decade.
I can't guarantee this will fix this silliness for everyone but I'd encourage trying to see if it works for you.