What do you expect? Uber has no way to authenticate you if email doesn't work.

Is Uber, by any chance, using "constantcontact.com" ("With Constant Contact, you can create effective email marketing...") for transaction emails? That's a terrible mistake, because they're basically a spammer and get blocked or opted-out. Bay Area FasTrak uses them for billing email, which causes some problems. An opt-out for all of Constant Contact will cause email sent through them to fail before it hits your own mail system.