The Column DateTimeOffSet allows date within range 0001-01-01 through 9999-12-31. This causes the problem.

Try the following to convert it to datetime:

Try_Cast([Created] as datetime)

to check the Range of the DateTimeOffSet:

Case when isDate(Try_Cast([Created] as datetime)) = 1 then Cast(0 as bit) else Cast(1 as bit) end as [isValidDate]