I am unable to Build any of the steps of my Jenkins job

I have a pre-written Jenkins job that has been working for about 7 years. Suddenly, it seems to stop mid-job and I am unable to restart any of the next steps. I click on the green Build button on the right and it does nothing, or selecting the step clicking Build Now does nothing either. Nothing works and I get no error messages.
Any ideas?

Have you looked in the Jenkins logs? Also, has anything in your environment changed, like OS upgrade, etc.?

I believe I figured it out. Our Jenkins linux server was near full on one of the mount points. There were several hundred Megs of space but not enough to run a full new job and all the files/backups that it requires.
As soon as I freed up space things seem to be working, although NOT advancing to the next step. That could be because I didn’t do all the steps sequentially, I did several by hand. Next month’s job will tell me if things are back to normal.
Thanks for the help Alex Earl.