Unable to assign Off Period to a Daily Work Schedule

Summary:

I am getting an error when I try to assign the resource exception to a daily elapsed work schedule.

Content (please ensure you mask any confidential information):

Dear Community,

Can you please advise?

We have a daily elapsed work schedule that is assigned at the legal entities level.

For one of these entities there are off period exceptions, i.e. extra off days the employees receive as a benefit. When I try to add the exceptions, I am getting an error:

There have been exceptions added in the past and I have followed the same steps, but there is nothing so obvious regarding what I am missing.: