There are a few things that can cause no recommendations to be shown when you use the preview functionality in the Personalization Portal.
- There are insufficient products to recommend from your product feed. You should check that your product feed contains all products available on site and that there are products in stock.
- The configuration of strategies and expressions is too restrictive. You should check that there is a selection of strategies to generate recommendations, and any expressions or hints you used are valid. If you use too many expressions in a campaign, it is possible that the selection of applicable products is so small that none of those products are suitable to recommend with your chosen strategies.
- The email address used for preview is unknown to Episerver Personalization (i.e. it has not previously been tracked on the site) and there are only personalized strategies in the configuration.
If you tried to preview recommendations for a user, who is unknown to the system, and you are only using personalized strategies in the configuration, then you must ensure a suitable fallback option is in place for the campaign. You can either add a Fallback set to all product positions or enable top-ups by ticking the "Use top-ups" box. The top-ups option will ensure that best sellers are shown to users for whom no behavior is available and there are no empty positions shown in the email campaign.