Chromecast connection Iphone

Good day, I used to play Deezer through Chromecast audio perfectly on my old Samsung, since 3 month I switch to Iphone 8 and even if I’m still able to play music through Chromecast, it doesn’t work good as before: problem is when display switch off and music keep playing, as son as the next song play (s.a. from a play list) iphone stop to follow the playlist, actually the music keep to play smoothly but when I switch on the display, deezer keep showing the last track was playing before to switch off the display, it’s like deezer is not able to follow the running tracks when iphone is on standby mode. Even worst if I run the music flow based on my favourite songs, it’s happen that Deezer doesn’t update the flow and the last song keep repeating forever. To get the control of the trucks again, I have to close Deezer app and open it again, than play any track, automatically is going to recognise the track playing in that moment through Chromecast, than I can control it again so far the Iphone is “active”. Not sure if problem is from Deezer or Iphone but I would like to address the problem to you hoping on a solution.
Thank you
Diego