Using Unreal Engine 4.21.2
1 - I created new Third Person game from the Unreal Engine template and named it FaceARSample
2 - I imported a skeletal mesh with blend shapes
3 - I added this to my DefaultEngine.ini:
4 - I packaged the project for iOS and it was successful. I was able to deploy it to my iphone.
5 - I activated Apple ARKit and Apple ARKit Face Support plugins
6 - I packaged the project for iOS and it failed (error log below)