No problems here with the U1 mini on a LAN with wifi to an iPhone running the current Lumin App... And Roon from a MacBookPro... What are you running the App on? iPhone, iPad or Android platform?
And what tuberist said about Peter’s support... Spot on... He is also pretty responsive here also... https://audiophilestyle.com/forums/topic/14016-lumin-audiophile-network-music-player/#comments
And what tuberist said about Peter’s support... Spot on... He is also pretty responsive here also... https://audiophilestyle.com/forums/topic/14016-lumin-audiophile-network-music-player/#comments