Problem with adding tracking information with tracking numbers

[bohdan_n]

When I send API call to

https://api.sandbox.paypal.com/v1/shipping/trackers-batch

I got next error

Spoiler

{"response":"[{\"name\":\"USER_BUSINESS_ERROR\",\"message\":\"Tracker Collection is Empty\",\"debug_id\":\"1966a3cd31dcb\",\"details\":[{\"location\":\"body\",\"issue\":\"TRACKER_COLLECTION_EMPTY\",\"description\":\"The request body is empty\"}

I put in body array with trackers. What is wrong?