If you’re getting SQL Server error 13680 that reads something like “Column ‘details’ on table ‘table_name’ is not of JSON data type, which is required to create a JSON index on it.” it looks like you’re trying to create a JSON index on a non-JSON column. You can only create JSON indexes on columns defined with the JSON type.
To fix this issue, be sure that the column is of JSON type before running CREATE JSON INDEX on it.