This is by design to avoid clipping of the audio signal being played from computer of DAW, and the direct monitor signals on hardware.
Choose “restart anyway” to proceed with restart.
This happens due to the "reopen windows" feature when macOS and OS X shuts down. See further details at https://support.apple.com/en-us/HT204005.
When H224 is the only audio device connected to the system, changing the sample rate via the H224 Control Panel App may result in playback error “can’t find audio device”. Simply attempt playback again after changing sample rate and in the future, avoid changing...