I've been experiencing this issue a lot with Xcode 11.3.1 when launching the App on the simulator, sometimes just restarting Xcode works, sometimes I have to restart my computer in order to make the app run again. It never happened on Xcode 11.1 tho.
I have noticed that on the simulator i got an error regarding "com.apple.commcenter.coretelephony.xpc". So the fix was to run this in terminal:
xcrun simctl spawn booted log config --mode "level:off" --subsystem com.apple.CoreTelephony
The downside is that you lose the auto layout warnings.