This is my expression but it is giving #ERROR for null DateExpired value

=SWITCH(
    IsNothing(Fields!DateExpired.Value), "N/A",
    Month(Fields!DateExpired.Value) = 2, "2/1/" & DatePart("yyyy", DateAdd("yyyy", -1, Fields!DateExpired.Value)),
    Month(Fields!DateExpired.Value) = 6, "6/1/" & DatePart("yyyy", DateAdd("yyyy", -1, Fields!DateExpired.Value)),
    Month(Fields!DateExpired.Value) = 8, "8/1/" & DatePart("yyyy", DateAdd("yyyy", -1, Fields!DateExpired.Value)),
    Month(Fields!DateExpired.Value) = 10, "10/1/" & DatePart("yyyy", DateAdd("yyyy", -1, Fields!DateExpired.Value)),
    Month(Fields!DateExpired.Value) = 12, "12/1/" & DatePart("yyyy", DateAdd("yyyy", -1, Fields!DateExpired.Value)),
    Fields!DateExpired.Value
)