SQL STUFF function roll up multiple rows

I am trying to combine a field when entries are made on the same day. The user may enter a message multiple times for a given Source on the same day. The resulting table is following -

What I would like to do is make one entry combining the MessageText for SourceID on the same day.

I have it where it will create an record for the SourceID and the same day however it will place every MessageText for that SourceID no matter what the date is. It does give one row for the same days. For instance the SourceID has 2 entries on 2012-11-08 on 1 on 2017-07-11. It creates a row for 2012-11-08 and one for 2017-07-11 however it places all 3 MessageText in the row.

My code is -

SELECT distinct  s.SourceID, stuff ( (select ', ' + rtrim(x.MessageText)
                                            from [AVData].[dbo].[LogCentralMessageData] x
                                            inner join AVData.[dbo].[Source] a on a.SourceID = t.SourceID
                                            inner join(select distinct max(m.CreatedOn)over (partition by r.SourceSiteID, Convert(date, m.CreatedOn)) as maxDate, r.SourceSiteID
                                                from [AVData].[dbo].[LogCentralMessageData] m 
                                                left join AVData.[dbo].[Source] r on r.SourceID = m.SourceID
                                                )  t on t.SourceSiteID = a.SourceSiteID and convert(date, t.maxDate) = Convert(date, x.CreatedOn)

                                            where x.SourceID = a.SourceID  

                                            for XML path('')), 1, 1, '') message_text
        ,convert(date, t.CreatedOn) as CreatedDate


from [AVData].[dbo].[LogCentralMessageData] t

left join AVData.[dbo].[Source] s on s.SourceID = t.SourceID
order by SourceID, CreatedDate

The following should do the trick...

SELECT 
    st1.SourceID,
    CAST(st1.CreatedOn AS DATE)
    message_text = STUFF(
                (SELECT 
                    CONCAT(', ', st2.MessageText)
                FROM 
                    dbo.SomeTable st2
                WHERE 
                    st1.SourceID = st2.SourceID
                    AND CAST(st1.CreatedOn AS DATE) = CAST(st2.CreatedOn AS DATE)
                ORDER BY 
                    st2.CtreatedOn
                FOR XML PATH ('')
                ), 1, 2, '')
FROM 
    dbo.SomeTable st1
GROUP BY 
    st1.SourceID,
    CAST(st1.CreatedOn AS DATE);