I recently got a miboc android tv and it works great except not getting detected by any of my phones over the same wifi network for casting, in google home app, or android tv remote app, but my pc, which is connected to same network with a lan cable can detect it and gives an option to cast video when i open youtube.
Sounds like your router doesn't let devices connected via wifi access other devices on your network. Dive into the settings on your router and fix that.