Welcome to the QuickBooks Community! Could you check your sync log for me? Here's how:
Sign in to QuickBooks Time, or in QuickBooks Online, go to Time, then Overview, and select Go to classic QuickBooks Time.
Select the QuickBooks dropdown, then View Sync Log.
The sync log can indicate the issue. Sometimes, it could be a payroll mapping error, permission error, missing employees error, etc. This article below breaks down the steps for each situation based on the log.