Stored Procedure - Field Not In Aggregate Function Or Group By

best solution for this stored procedure query.I'm getting the following error:

Column 'dbo.Applicants.submitted' is invalid in the select list because it is not contained in an aggregate function and there is no GROUP BY clause. Here is my select query:

Code:
SELECT DISTINCT DATENAME(MONTH, submitted) AS mon, MAX(submitted) AS SubmitDate
FROM dbo.Applicants
WHERE ((CASE WHEN MONTH(submitted) > 8 THEN YEAR(submitted) + 1 ELSE YEAR(submitted) END) = @AcYr)
ORDER BY SubmitDate

The submitted field is a date field.I don't want to add the submitted field to Group By as I want to group by month not date.Is there any solution to avoid grouping by date?