Why is the time tab in layer properties greyed out?

[GISLearner]

I ran the Network Analyst - create drive time areas on a layer, which contains time data. And I want to create a time related animation on those drive time polygons. However, the entire time tab in the polygon layer's properties is greyed out. Why is that and what's the workaround? Any help is appreciated

[David_Brooks]

@GISLearner Have you enabled time on your layer in the layer properties?

 

[GISLearner]

This entire Time tab is greyed out, so I cant change the Layer Time or the Time Field or any of those buttons

[David_Brooks]

@GISLearner , are there any fields in your data with a Date format? You can't work with Time without it.