How to solve Error 'KafkaJSONParser() does not exist, or permission is denied for KafkaJSONParse'

Hi,

we use the KafkaJSONParser in a COPY query using KafkaSource and we get the following error:
[42883] ERROR: Function KafkaJSONParser() does not exist, or permission is denied for KafkaJSONParser()

How to I grant permissions to the user to the KafkaJSONParser?
I tried, similarly to KafkaSource, but the did not work. However, I granted permissons to kafkalib and KafkaSource:

GRANT USAGE ON library kafkalib to <user>;
GRANT EXECUTE ON source KafkaSource() to <user>;