Please do try these troubleshooting steps that may help in solving the issue.
- While the laptop is connected to your TV press the Windows key + P at the same time and select between Extended or Duplicate display.
- If it doesn't work do a clean install of the graphics card driver.
- Go to Device Manager and uninstall the graphics driver.
- Check Programs and Features as well and uninstall anything related to the graphics card.
- Next is to download and install the latest driver. (Nvidia or AMD)
- Reboot your laptop once the latest driver has been installed.
- After the reboot do press the Windows key + P at the same time again then see if it will work or not.