Playing new Track not working

[Nova1545]

Im using this to try to play the track, item is a FullTrack. Pausing itself works but I cannot get it to play a new track
Spotify.Player.ResumePlayback(new PlayerResumePlaybackRequest() { ContextUri = item.Uri })

Have I done something wrong? Ive look through the docs and have been unable to find anything regarding playing a new track
Using API V 6.2.1

[Nova1545]

Spotify.Player.ResumePlayback(new PlayerResumePlaybackRequest() { Uris = new List<string> { item.Uri }, OffsetParam = null, PositionMs = 0, });
Needed to set OffsetParam to null and make sure there is an active player