I see your values in all of your columns are left justified, including column G which is the important one in this case. The contents in the cells line up on the left side of the cells. Text naturally is left justified. Numeric values are naturally right justified like you see in cell H13 that has your numeric formula that is forcing it to be a numeric cell. This leads me to believe that your entire table is formatted as text. Numeric functions such as SUM, SUMIF, etc. ignore text. Even if the text looks like a number to you and me, it will be ignored.
You have mixed data in column G but it appears you can format the entire column as type "number" and this should fix this particular problem with SUMIFS. "Automatic" should also do it. It appears it was manually changed to text, otherwise the default "automatic" format would have automatically matched the type of data you entered and the numbers would be treated as numbers. When you change the cell format, all of the values in that column should switch to right justified.
Just to cover all bases here, if the values in column G are the result of formulas (not manually typed in), the formulas will have to be modified to generate numeric values, not text. The VALUE function is one way to do that.