TCL Roku 40” tv buffers and sometimes goes back to the Home Screen.

My 40” TCL ROKU tv keeps buffering and sometimes goes back to the home page. 
I have excellent wi-fi signal. 
I called support and she had me try a couple of things and I told her sometimes it takes 20 minutes before it buffers. She said then she would call me back in a little while. 
she got me on that one. 
can I connect the tv directly up with coax to Spectrum? I would use a two way splitter in the basement.