You may have missed it as it was buried inside a recent thread. comment by /u/crackheadbimbo offers a very plausible explanation why MiBox fails to pass Netflix streams when other devices are unaffected.
"Don't that tell you something about how netflix disses Mi like a red-headed stepchild. All these other boxes have a good rep. Netflix forces the lowly Mi to prove its DRM credentials every time. If you have a no-name POS TV, it will fail the Netflix check every time. Don't doubt for one second Netflix knows exactly who they talking to. You should be ragging on Netflix. Mi is doing the best it can. That's the real deal in re that DRM stuff. It is an end-to end security protocol."
Other companies are able to fulfill Netflix's checks/requirements. Don't blame them for what can be attributed to Xaomi's and/or a TV manufacturer's incompetency.