If you already have a column with the date of the downtown, drag it to columns next to Month(Resolved). Then make your chart is a dual axis.
Once you've done that, you can play around with the Marks to see what works best for what you're looking for. I have a feeling it might be a really thin bar chart or some variation of Gantt chart.
See attached workbook for quick example.
BarDate.twbx 1.2 MB