My router connects to my ipad2 just fine but the ipad2 does not connect to the mixer. mixer using V1.90 and ipad2 using V1.91. When I use my Ipad mini 2 it connects fine. I am using DHCP.
I use the iPad 2 all the time with mine. Confirm that the Qu-16’s IP address is not static, and that if it is, that it matches the current subnet being used by your router. If the mixer’s IP is part of a different subnet, then that would explain your problem.