My phone keeps getting "insufficent space on device" message

[AC Question]

Im trying to install an 27.43 mb app and my storage says my avalible space is 400 mb however whenever i try to install the app it keeps saying "insfficent space"

 

[cpaight]

I've had this issue too, it seems to happen if I'm under 500mb....not sure of the cause, but I'll typically clear out my cache or the data from a large app, and then install the app once back above the 500mb mark.