When looking at graph on a Dashboard, even in the expanded view, a user cannot clearly read the information when including a large number of columns. The labels are pushed together and overlapping, and the graph labels are therefore unreadable. This only happens for Column or Line graphs and does not affect Pie graphs.
Select fewer values items to be included in the Dashboard graph
Change the Graph type from Line or Column to Pie. The labels will then be visible across the bottom in the legend without overlapping.