Teapplix supports getting shipping labels from TikTok, this is a special type of order called 'Upgraded TikTok Shipping', where 'shipping label is provided by TikTok'. Such orders are normally not downloaded by Teapplix. However, if you go to your integrations page, you will find a check box that turns on download for such orders. Any 'Upgraded TikTok Shipping' order, Teapplix will get labels from TikTok during the print process.
TikTok is making this mandatory. You need to turn this on on your TikTok seller dashboard to enable it.