Your custom state ‘Genre’ is of type ‘Genre’
But your Input Text Genre is (presumably) a text.
The value of the custom state needs to be an actual (existing) Genre from your database.
So if you’re using a text input to find a Genre, you’ll need to search the database for a Genre, where a specified field (a text value) matches the input texts value, and select the first item.
So your custom state value should be:
new_artist’s Genre: plus item
search for Genres: name (for example) = Input Text Genre’s value
:First Item