I am getting this error when i try to pay an employee

We can perform some troubleshooting steps to resolve the error message you receive when trying to pay an employee in QuickBooks Online (QBO), @hari4. I'm here to provide the step-by-step process.

This message indicates that a form has already been filed for this period. If you're running payroll for future pay periods, try logging in to your account through a private or incognito browser. Too much historical data can cause discrepancies that affect the display and performance of QuickBooks.

To verify if this is a browser-related issue, open one of these browsers using the following keyboard shortcuts:

• Google Chrome: Ctrl + Shift + N
• Safari 11 or newer: ⌘ + Shift + N
• Mozilla Firefox: Shift + Ctrl + P
• Microsoft Edge: Ctrl + Shift + N

If it works, clear the cache of your original browser to start fresh, or use another supported, up-to-date browser to narrow down the results.

Otherwise, I recommend reaching out to our live QuickBooks Online Payroll Support Team if you're trying to correct your previous payroll. They are equipped to promptly address your payroll concerns. 

Explore QuickBooks Payroll if you're interested in streamlining your payroll processing. Time-tracking features and faster direct deposits can be a game-changer for your business.

Drop by this thread again if you have future concerns running your payroll. I'm more determined to help.