This is actually a growing concern for many in the IT industry. Unless you are paying one of the big providers to host your email service, you are at an ever increasing risk of having your emails blocked by those same big providers. This goes against the spirit of net neutrality and is reducing competition and making it harder for smaller service providers to survive.
Most email providers allow you to add addresses to your allow list, flagging that messages from those addresses should not be blocked. Perhaps look at configuring that for the AAM emails?