Here are some possible causes.
<The Illustration You Are Using>
The illustration may not load properly if many parts of the face are hidden or have too many gradations.
If you have trouble loading or preparing illustrations, please check the [Illustration Guidebook] from the "View Illustration Guidelines here" link at the bottom of the illustration upload screen.
If the illustration is loaded correctly but the eyes and mouth do not move properly, please go to the settings tab and adjust the eye and mouth movements on the stream preparation screen.
<Your Device>
IRIAM recommends Face ID-enabled devices, which can reflect your facial expressions on the illustration with higher accuracy.
The iPhone X and above supports Face ID. Please refer to Apple's "Compare iPhone models" page for details on whether your device supports Face ID.