An error is displayed when uploading custom emojis

Summary

When trying to add custom emojis via the site's administration (https://<site-URL>.atlassian.net/admin > Emojis), a warning error is displayed:

Diagnosis

• Check if this is happening with any emojis.

• In Confluence, when editing a page to add custom emojis directly from there, check if the Add your own emoji option is not displayed at all.

Cause

The toggle to allow users adding custom emojis is off:

Solution

Toggle the Allow people to add custom emojis option on and try to upload the emoji again.