It's my priority to help you run payroll with no issues in QuickBooks Online. In order to do so, I'll be needing some more details to narrow down this concern.
May I know if you receive any error message? When did you start experiencing this problem? Any further details about this matter are much appreciated.
For now, let's try browsing from a Private Window. This prevents the browser from collecting cache files (cookies) gained from files that were gathered. Since these files can often become outdated, Private Window allows you to access QuickBooks with a fresh slate to see if it resolves the issue.
If the employee details are now showing up, I suggest going back to your regular browser and clear its cache. Doing this will eliminate the unnecessary data reloads the program.
Thanks for reaching back out to the QuickBooks Community. If the troubleshooting steps didn't help that my colleague provided above, then I recommend contacting our Customer Support Team. They have additional tools to help look further into your account to see why only one employee is showing up to run payroll. Here's how:
Go to the Help icon in the top right-hand corner.
Tap the Contact Us button.
Type in your question and hit Let's Talk.
Scroll down and choose to Get a Callback.
I'm only a post away if you have any other questions. The Community is always here to have your back!