"I see nothing in the bar"
In FTM2017, on the Sync toolbar icon on the top right corner, you should see a little connection status "flash" - either green, orange or red (although you can turn it off in Options, and I think it was only introduced in the 23.1 update, so if you haven't updated and you're still on 23.0 you won't see that).
Either way, when you click on the icon and select "Sync now" or click the "Sync now" button on the Tree Plan workspace, if the tree isn't already in sync you'll get a sync popup dialog window showing the current status - even if it's a green "all ok".
At the moment, almost everyone seems to be getting red (sync unavailable) or orange (sync not recommended), as shown in the attached screenshot, which also shows the orange flag on the sync icon.
Ancestry are currently upgrading their servers, and hopefully the situation will be resolved very soon.