Try reformatting cell Table 2::A2 to text.
You might consider the same thing for Table 1:A2. It does not play a role in your formula but I assume it is used for something.
Looking at your tables,
- Expense Log::Month has the months aligned to the left of the cell. This leads me to believe they are text.
- Table 2::A has the months aligned to the right. This leads me to believe they are date&time values with only the month being displayed.
- Table 1 doesn't seem to be doing anything here but it also has the month aligned to the right of the cell
The text "June" is not equal to the date "June 1, 2021" so it is finding no matching values for your SUMIFS.
If you type "June" into a cell that has not been pre-formatted as text, it will be turned into June 1 of the current year. If you look at the cell format it will be "automatic" but will also have settings for the date and time. If you format the cell as text before typing "June" it will stay as "June".