I find with Upwork messages if you clear you cookies they often come back. What I would do first is open your browser in incognito mode and login to upwork and see if it comes up. No sense clearing your cookies for no reason.
I was offered a 1 month (I think) free trail of Client Plus when I first loged into my Upwork account. I thought I would be able to explore a bit and decide later. Now I can not find any way to activate this free trail. Could you assist me? Thanks