Ensure you've connected your blog in Menu -> Connect my Blog. You should see the API key.
Ensure that at least one article has Published status.
Use the Force Sync button in Menu -> Blog Sync Status to synchronize articles.
Check the server/client cache on your app side.
Ensure that the page parameter is zero-based (0 = first page, 1 = second page, etc.), you probably use 1 for the first page:
const articles = await client.getArticles(page, limit);