The barriers that Amazon is facing in the European Union is that it has an inquiry that if it is using the third party apps at the cost of other retailers
Explanation:
Amazon has been reported that they use the third party apps to gain the attention of the customers and they sell the products at the cost of the other retailers and the other third party users face a huge loss
And they had opened a formal investment by the antitrust investigation to check the usage of the third party apps that if amazon used these to promote its own product at the expense of others