We've got some tapo bulbs and sockets running on Google Nest/Home. 

I have the tapo app on my phone. Occasionally my wife tries to turn on the bulbs or sockets when I am out and it says that the bulbs cannot be reached or are offline etc. When I get home they then work fine. 

Does my phone need to be on the wifi for the tapo bulbs etc to work? If my wife installs the tapo app on her phone and logs on with the same account will that solve the problem? Can two people log onto the same account?