Select the name of the employee to open their profile.
Tick the edit (pencil) icon beside Pay.
Next to the withholding section, click the edit (pencil) icon.
Check the Federal Filing Status/State Filing Status.
In addition, you can also run a payroll report to check the details of your employee. I suggest you use the Payroll Summary by Employee report to view a comprehensive report of wages, deductions, and tax info.
I appreciate what you've done to fix this. Since it's not working, I'd recommend contacting our QuickBooks Online Support Team. They have the tools to verify your account and further check what has caused this to give a resolution on this matter.
Here's how to reach them:
Select the ? Help button.
Choose Talk to human.
Enter your concern in the chat box such as, "Federal tax in October was not withheld," click the Send icon.
Select the button for I still need a human.
Click Contact us.
Choose how you want to be assisted, either Send a message or Get a callback.
Enter your details for verification and confirm your request.
I've added a screenshot for additional reference:
I've included this article that may help you in your future task about tracking specific aspects of your business' wages and expenses: Run payroll reports.
I'll be here if you have other questions about QuickBooks. Take care always.