For some reason when I try to invite someone to the Time Tracking, nobody is listed, even newly added contractors & employees

I'm here to ensure you can invite your workers, james. 

To use the time tracking feature, we have to first, enable which time tracking options you want:

1. Go to Time.
2. Choose if you want basic time tracking in QuickBooks Online, or if you want to try a QuickBooks Time account with more time tracking features. Either way, you can access timesheets from QuickBooks Online. 
3. Select Get Started. 

Then, we can adjust your time-tracking preferences. 

However, if you've already completed this action, but still encountered the same results, I recommend using an incognito browser. Doing so will prevent the browser history from being saved. 

You can refer to the following keyboard shortcuts based on your browser type:

• Google Chrome: Ctrl + Shift + N
• Mozilla Firefox: Ctrl + Shift + P
• Microsoft Edge: Ctrl + Shift + P
• Safari: Command + Shift + N

If the private browsing session works, clear the browser's cache so the system can restart. This task is also possible in other supported, up-to-date browsers. Clearing the cache will reboot the system, allowing you to work with a clean slate.  

Also, may I ask if you've encountered a specific error when inviting your workers to time tracking? I'll patiently wait for the details and your response on this. 

Moreover, you can access time-tracking reports. This lets you get a hold of your employee's activities. 

Let me know if you have follow-up concerns about managing your workers. I'll be here to lend a hand. Stay safe always!