Hello Toli, and thank you for posting to our community!
Our test emails use generic information which is not specifically gathered from your Stores & Orders settings. The test emails are intended to give you a preview of formatting and placement of information. For example, you will not see your store logo but rather a place holder. Likewise, the tracking number will be invalid.
This is explained further in the notes at the bottom of the link below:
I did notice, however that you created a test order last night and post dated for today. The confirmation email for that post dated label will be sent at the same time the label was actually created yesterday.
Once you receive the email confirmation for that order, the tracking number and link should work correctly along with any other Store specific information.
Thank you and happy shipping!