You should close Android Studio / Unreal Engine Editor or any other process that uses adb bridge.
You may need to call sudo spctl --master-disable on recent version of Mac OS before use.
Please make sure your apk's debuggable flag is set to true. Unless your device is rooted.
Make sure your apk has Internet Access, profiler need this to send data to your PC.
Profiler will print simple logs in DashBoard tab's console window.
And will print some more logs under installation folder.
Use adb logcat -s Loli to see application runtime logs.
Use adb logcat -s xhook to see if your target library is hooked correctly.
Always save these logs when you're in trouble. It helps us to identify the key problem.