iPhone can not run the WatchKit extension

when the Xcode run the WatchKit extension, it report a problem, iPhone can not run the WatchKit extension, and the recovery suggestion is : the WatchKit extension's architecture (armv7k,arm64_32) include none that iPhone can execute (arm64e,arm64v8,arm64,armv8)
I used the IPhone11 (14.0), iwatch5(7.0), and Xcode12
How can I solve this issue?
The error message was totally misleading. At the very beginning to debug an Apple Watch app, we should use target of the WatchKit Extension. However, I didn't know since when, to debug we should use the Watch App target instead of the WatchKit Extension.
iPhone can not run the WatchKit extension
 
 
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