Telkom Lit TV Box

Hi, can someone advise, I have the Telkom Lit Tv box and it says its has a built in Chrome Cast, I was playing around and somehow it connected and I xould watch what I was doing on my phone via the box.. How would I connect it again as I cannot get it right again to link it..?

when I go in settings or the app of chrome cast tells me app close due to error

thanks