I use the trail version of InDesign
Yesterday I tried the "publish on line" button which asked me to log in on creative cloud what i had already done, and always the same
Today, worst, the "publish on line" button is not present anymore on my toolbar.
Is it because i use the trail version?
You can use Publish Online in the trial version with your Adobe ID.
If it's not working today, go to the Creative Cloud desktop app (menu bar on Mac, task bar in Windows). Click <gear icon> > Preferences > General. Sign Out from your Adobe ID, then sign in again. This works for most people.