Discovered that I cannot use my external mouse consistently on chess.com.  I am old fogy and don't do so hot with the mouse pad.  But when I try to capture with the external mouse it doesn't work consistently.  (I've tried this on both laptop and desktop PCs.)  I can make any move I want with the external mouse as long as it is not a capture.  If I want to make a capture and make sure it works I'd better use the pad.  No wonder my rating was so low!

 I just now realized that this is in the help & support category.  I'm out of here.