CSV Upload errors, even after adding all attribute values

I’m trying to add custom attributes using a CSV. I’m using the header additional_attributes.

I have attributes called “main category” and “sub_category”, and they’re in the additional_attributes column as

main_category="category name",sub_category="subcategory name"

I used the api to upload all of the product options, but I’m still getting the error:

Value for 'main_category' attribute contains incorrect value, see acceptable values on settings specified for Admin in row(s)

and it lists all of the rows.

I’ve reindexed, cleaned the magento cache, and flushed redis cache, but the error stays the same.

Any ideas?

Thanks