This should be because you didn't open the "floating window" with the permission of Tik Tok. We can open the floating window of Tik Tok in the mobile phone settings, and then a floating window will appear in the live broadcast.

Mobile phone: Huawei p40pro

Tik Tok version: 24.0.0

1, we open the settings in the phone, and then slide down to find applications and services.

2. On the Applications and Services page, click Application Management.

3. Then we find Tik Tok in the open page and click it.

4. After opening Tik Tok Management, click Permission.

5. Find the floating window in Tik Tok permission and click it.

6. Finally, we can click Allow.