If you go to Window > Devices, it'll tell you a more detailed error message under your device. For me it was:
"To run on this device, please update to a version of Xcode that supports iOS 13.6.1. You can download Xcode from the Mac App Store or the Apple Developer website."
I started getting this problem once my iPhone updated to 13.6.1 overnight, and apparently my Xcode version (11.4) is too old to run with 13.6.1.
bryanwbear
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