Apparently, with the latest IOS update, my version of Xcode could not build due to the following error.
Could not locate device support files. This iPhone 7 Plus (Model 1661, 1784, 1785, 1786) is running iOS 11.3 (15E216), which may not be supported by this version of Xcode.
Tried to install Xcode 9.3 via this link https://developer.apple.com/download/more/. But as it turns out, my Mac OS version sees the update as an incompatible version. Running on Sierra 10.12.6