Why can't I install third party apps on my iPhone

[iMore Question]

On my phone I have updated to iOS 10 but even before that I had this problem. I like to use certain emulators on my iPhone such as gba4ios and nds4ios. Yes they are signed yes they work for my iOS version but every damn time I try it it goes about 1/4 the way and then says cannot be downloaded at this time. Can anyone help me?

 

[Just_Me_D]

The problem may reside with the server you're trying to download them from. Do you have a fast internet connection? Have you tried rebooting the device, the modem and the router?