It is not recommended to use remote debugging on devices connected to DHM's with latency greater than ~50ms (round trip).
In order to perform remote debugging you will need to generate symbols matching the device build id:
1. Click on START DEBUGGING to generate symbols.
After you click the button a folder with iOS version + build ID will be created at /Users/USER_NAME/Library/Developers/Xcode/iOS DeviceSupport/IOS_VERSION +BUILD_ID
containing device date. This operation will generate symbols and take up to 1 minute.
2. Click on start.
If you click on DOWNLOAD FROM DEVICE Xcode will still generate symbols, however, it will fetch data from a device and can take up to 2 hours.