Thanks for your advices!
I checked attribute, no attribute was added. Then I checked Pages, and there’s a page with slug of “product”, I think that causes a conflict with Woocommerce product permalink. So I made the modification:
Page slug: ‘product’ → ‘enterprise-product’
Product Permalinks: ‘/product/%category%/’ → ‘/%category%/’
Then category displays, but single product still 404. And another page ‘https://buydroneuavs.com/shop-online/’ 404, too, while it can display normally before.
Then I modified the Product permalinks back to ‘/product/%category%/’, now everything displays well. I don’t know why. Will observe if 404 error occurs again.
