Maximum DATEDIFF in MI (minutes)

I keep receiving an error when execute a query:

The datediff function resulted in an overflow. The number of dateparts separating two date/time instances is too large. Try to use datediff with a less precise datepart.

The query has worked for some time (years to be exact):

SELECTDISTINCT

 A.OPENDATEASOPEN_DATE,

 A.CLOSEDDATEASCLOSED_DATE,

CASEWHENISNULL(A.CLOSEDDATE,'1776-07-04') ='1776-07-04'ORDATEDIFF(MI,OPENDATE, A.CLOSEDDATE)< 0 THEN NULL

  WHENDATEDIFF(MI,OPENDATE, A.CLOSEDDATE)BETWEEN 0 AND 1440THEN'Y'

  ELSE'N'

 ENDAS24HR_flg,

FROM

 tableA

LEFTJOIN

 tableCON A.ID =C.ID

WHERE

  C.PROCESS_FLAG= 1

What’s the maximum value you can have when getting the datediff in minutes? Let’s assume I HAVE to use minutes in the query