It says my certificate was superceded and all data is invalid or something like that. I am going to ask arrl what is going on.
AH! I had this happen a couple of months ago--I had mostly been using a desktop for logging and LOTW, and that desktop blew up. I went to a couple of laptops, and had the same problem, upload didn't work and when I looked at the activity log, it told me I was using an outdated certificate.
I did a clean install of the LOTW software on a linux laptop, downloaded my right certificates from the LOTW website, and I was back in business very quickly. It took me a lot longer to figure out what my problem was than to fix it.
GL HTH! --ken