Does not fulfill the input condition in MS Access 2007, what is the error?

Question

Microsoft Access

There are 2 date columns Start Date and End Date.
I set in the Start date field "Value condition": <='End date'
And the error text in the "Error message"
I do the same in the End date, but in the condition I set: >='Start date'
At the same time, the conditions do not work out. What could be the problem?