Have you tried disconnecting your Naim equipment from mains power, then re-boot your Modem / router.
Wait for that to finish starting (5 minutes usually) then reconnect your Naim equipment and see if it works then.
Sometimes, deleting the app from your phone or tablet / iPad and reinstalling it can help as well.
The only other thing I can think of is to perform a factory reset to your Naim device.
When you have factory reset try setting up the item as a new device using the Naim app rather than the front panel or remote (and with the Naim app connected to the WiFi network you want to use). That has worked for me
Also had this problem…but only the Muso 2 …our original Qb was not affected
Tried everything possible…power down …remove and add as new product to no avail.
What did sort the problem was to unplug the router for five minutes and re start….hoping that I am not tempting fate posting this as to date no other issues have arisen.
Steve