QueryPipeline has no data when opening in content browser
I have created a new Query Pipeline for Recommendations. So, I've added EventRecommendation Model and when I tried opening this pipeline in contentBrowser I get no data.
In your sandbox, I highly doubt you will actually get recommendations. You need to have visits on your page to recommend content relevant to the user’s current visit history. The required data is collected each time a user visits a page containing the Page View Analytics component. You might want to check Pushing Coveo Analytics Page View Events for starters.
Ensure that page view and search action events are being pushed to the Coveo Cloud usage analytics service for your organization (see Coveo Machine Learning Event Recommendations Deployment Overview).
If no usage analytics data is available, there will be no recommendations. When you just start gathering data, recommendations will progressively improve as more data becomes available each time the model is retrained (see Training and Retraining).
So, it is normal that you do not have any recommendations.