REST Create new TestStep and new line in text

I'm using Zephyr Squad's REST API to post test steps. How can I post new lines? When I tried to put "\n" (like "First line\nSecond line"), Zephyr Squad returned 400 bad request. This is the REST API method I'm using: https://zephyrsquad.docs.apiary.io/#reference/teststep/create-and-get-all-teststep/create-new-teststep

When I put new line in the browser and get test steps with REST API, new lines are "\n".