Hello,
I've just tried this out and got it to work - in your Start and End time, you have to provide the date as well as the time. In your case, I would assume you want this to be the current date. You can use dynamic content and formulas for that - the formulas I'm using are utcNow() which gives you the current date, formatDateTime() to format the date and time and concat() to concatenate the current date with the timestamp you want:
I've set Start Time to:
concat(formatDateTime(utcNow(), 'yyyy-MM-dd'), 'T','17:00:00-00:00')
I've set End time to (this adds an extra day to the current date for tomorrow using addDays)
concat(formatDateTime(addDays(utcNow(), 1), 'yyyy-MM-dd'), 'T','09:00:00-00:00')
If you click on Start Time/End Time and select dynamic content and then "Expression" and copy the above formula in the bar, that should work for you.
Your action box will look like this then
If expressions are new to you here's a blog about them:
https://flow.microsoft.com/en-us/blog/use-expressions-in-actions/
