sumifs() problem in Office 365

I have the following formula in a workbook, can't make it work, what am I doing wrong?

=SUMIFS(Deposits[Amount],Deposits[ACCOUNT ID],'='[@[Account ID]],month(Deposits[DATE]),month(Cashflow_Income[[#Headers],'='[Dec 13]]))

Would appreciate any help I can get. I am trying to summarize information by month and account id.

You don't actually need the equals sign for an equal condition but, if you have it, it should be in double quotes. And you' denied to concatenate it to the field using &. What you don't need is single quotes.

Best bet is to remove the '=' in both instances.

Regards, TMS