Cannot connect to Naim Uniti Atom

Hi there - currently on the 30 day trial. Was working OK with everything connected via Wi-Fi - both my Mac and the Atom and using iPad as remote. I changed the router over the weekend to improve general WiFI around the house and since then Audirvana doesn’t see my Atom - only option is to play via the computer. I’m also trialling Roon - this reconnected absolutely fine, Apple Music finds the device also OK. Any pointers please.