Cookie expires not working

I am simply trying to set the expires date to one month in the future but it won't seem to work. Here is the code.

Code:

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Dim MyCookie As New HttpCookie("MobileLogin")
MyCookie.Values("UserID") = Trim(CType(Table1.Rows(0).Cells(1).Controls(0), TextBox).Text)
                MyCookie.Values("LastUpdated") = Date.Now.AddDays(30).ToString
                MyCookie.Expires = Date.Now.AddDays(30).ToString
                MyCookie.Values("UserName") = Trim(datRead.Item("UserName"))
                MyCookie.Values("Store") = datRead.Item("Store")
                MyCookie.Values("AccessLevel") = datRead.Item("AccessLevel")
                MyCookie.Values("TempLevel") = datRead.Item("TempLevel")
                MyCookie.Values("TempStore") = datRead.Item("TempStore")
                MyCookie.Values("JobCode") = datRead.Item("JobCode")
                MyCookie.Values("EmployeeNum") = datRead.Item("EmployeeNum")
                MyCookie.Expires = DateTime.Now.AddDays(30)
                Response.Cookies.Add(MyCookie)

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I have tried many different formats for the date but no matter what I do when checking the expires date with this:

Code:

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Request.Cookies("MyMobile").Expires

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Comes back as this "#12:00:00 AM#"

Anyone know why?