I am struggling to get my column validation to be accepted.

This is the logic I am trying to replicate:

IF "Status" = "Successful" THEN "Date Completed" must be filled out AND "Date Completed" IS NOT in the future.

 
Here is the formula I currently have:

 =IF(Status="Successful",
 IF([Date Completed]<>"",TRUE,FALSE),TRUE)
 AND
 =[Date Completed]<=Today()