Emoji can seem to disappear when a device or app does not support the emoji data it receives. Instead of artwork, the user may see an empty box, a question mark or separate characters.
This often happens with newer emoji, ZWJ sequences, flags, skin tone combinations or presentation variants. The sender may see the emoji correctly, while the receiver uses older software that lacks the needed font support.
Emoji can also appear differently after system updates, because platforms redraw artwork over time. The emoji usually still exists, but its design may change.
If an emoji is missing, updating the operating system, browser or app often fixes the display. For sequence-based emoji, see ZWJ emoji sequences and emoji variants.