Let's work together so you can send invitation emails successfully to your time tracking users, Dee.
To begin with, could you please share if you encountered any errors when sending an invitation to the new user? This will help me provide a more precise solution.
When adding a new user for the time-tracking role, let's ensure that we sync the team member correctly. Here's how:
- From the Add user, click View all permissions.
- Click Sync team member.
- Choose either an existing team or add a new one.
- Once done, select Sync.

If the user is already synced and the issue persists, I recommend clearing your browser's cache to remove excessive data buildup that might impact QuickBooks Online’s performance. If the problem continues, try switching to a different supported browser.
If your invited user didn't receive the email invitation, or is unable to locate it, you can refer to this article: Invited user didn't receive your email invitation.
You can also review this article to learn about usage limits in QuickBooks Online, which outline the maximum number of accounts or users allowed: Learn about usage limits in QuickBooks Online.
Feel free to revisit this thread if you have additional questions.