Xcode Error: Failed _shouldMakeReadyForDevelopment check even though device is not locked by passcode

I encountered an error while trying to test my iOS App on a Physical Device via WiFi (no cable connection!)

Here are the error message & the error description

Failed _shouldMakeReadyForDevelopment check even though device is not locked by passcode.

allowsSecureServices: 1. isConnected: 0. Platform: DVTPlatform:0x7f9d3df95a50:'com.apple.platform.iphoneos':<DVTFilePath:0x7f9d3df959d0:'/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform'>. DTDKDeviceIdentifierIsIDID: 0

Does anyone of you have an idea what causes this error and how to fix it? Thanks for your help in advance!