Latest questions about "xy chart labeler"

I get this error when I launch XY Chart labeler in Excel. I have been using it for several years, and just received this error. Nothing that I know of has changed in my process.

I am using the XY Chart Labeler program and I can't select all items to change font size or style at the same time, so I have to do this change for each word which is impossible as there are too many...