When Jungle Scout doesn't display a product's rank, sales or revenue, it is typically due to one of these reasons:
1) Smile.amazon website is in use, or the smile extension is enabled. Jungle Scout does not work when the Smile app is in use on the Amazon store.
2) Amazon did not publish a rank in the parent category. If there is no rank in a product's parent category, then Jungle Scout can't estimate sales or revenue, since we use Amazon's Best Seller Rank to determine those estimates. It's important to note the rank must be in the parent category, and not a subcategory. Jungle Scout doesn't estimate sales and revenue for sub-category rankings because those rankings fluctuate on an almost constant basis, making accuracy next to impossible.
You can check for a parent category rank by clicking on an item, scrolling down to the item details and looking for this:
3) Amazon's Translator is on. The extension will not work properly when Amazon's translator is on...because the software is coded to read the information on each listing in the native language of each marketplace. If the translator is on, the extension can't 'read' the data and categories.
So, if you're in amazon.com, the listings need to be in English. If you are in amazon.de, the listings have to be viewed in German. And if you are in amazon.es, the listings must be in Spanish.
If your translator is on, then when you turn it off you should see the estimates populate.