The dictionary style (.stylx) is an older version that is no longer supported and cannot be shared. The dictionary must be version 3.0.0 or later.
Solution
To change the dictionary version, open the style file (.stylx) in an SQLite database editor and change the dictionary version in the metadata. Update the Arcade script used to drive the dictionary. See Upgrading dictionary styles from a previous version for more information.
More information
To learn more about dictionaries, see Dictionary symbology and Dictionary renderer toolkit. For more information, see Share a web style and Analyze your GIS resource.