Access fails to group data!
The grouping may be the same, but you have an asterisk (shortcut for select all field, but the sequence is unkown what prevents grouping and aggregation) at the end of your selected fields that causes the error.

If you want to get the sum of Transaction_Amount per ID you just group by ID not by Transaction_Amount

SELECT
    Sum([Account Transactions].Transaction_Amount) As SumAmount
  , [Account Transactions].ID
FROM
    [Account Transactions]
GROUP BY
    [Account Transactions].ID