It is possible that the TV does not support screen sharing. You can try using an additional device like Miracast or Chromecast to mirror your phone. Alternately, it is possible that the TV can support screen mirroring of an iPhone, and not an android phone. If you encounter this issue, then there are workarounds you can do such as using Miracast or connecting via an HDMI cable. If you're sure that your smart TV should be able to connect, then double-check the manual to see if there is anything missing or contact the manufacturer directly.