I have tried repeatedly to set 'Away' on one of my Smart Plugs with no success.

I get various errors like; Your Smart Plug has a Conflicting Event with the Start or End Time or Away mode must start and end on the same day. I have tried to set Away to come on at sunset and turn off at 22:30 every day or on one day only. I've tried to set it to come on at Sunset and turn off at Sunrise and also to come on at sunrise and turn off at sunset. What am I doing wrong? The only thing that seems to work is setting specific time for Start and End. In-app Help says Away mode start and end times can be set to sunrise or sunset.