Trying to set presentation Expiry Date to file objects and getting the error "Value does not fall within the expected range" in microsoft.office.interop.powerpoint

Used the below code in VS 2019 C# .Net Framework

Microsoft.Office.Interop.PowerPoint.Application app = new Microsoft.Office.Interop.PowerPoint.Application();
Microsoft.Office.Interop.PowerPoint.Presentation appDoc = app.Presentations.Open(@"C:\Users\Doc1.pptx");
foreach (Microsoft.Office.Core.UserPermission usr in appDoc.Permission)
{
var userItem = usr.UserId;
DateTime dt = new DateTime();
IFormatProvider culture = new System.Globalization.CultureInfo("en-us", true);
dt = DateTime.ParseExact("05-06-2021", "dd-MM-yyyy", culture);
usr.ExpirationDate = dt;
}
Getting error when I tried to assign date in Microsoft.Office.Core.UserPermission.ExpirationDate