There are multiple reasons you may see a balance in TNTAP.
If a return has been filed but no payment has been submitted for that period, you will see a balance when you log into TNTAP. When submitting returns and payments, you will receive two separate confirmations with different confirmation numbers. One confirmation is to confirm that you have filed a return and the other confirmation is to confirm that you have submitted a payment.
You may also see a balance if you filed a return but submitted a payment for a less than the amount due on your return.
The screen you are viewing in TNTAP also directly impacts the information displayed. Your taxpayer springboard (the screen that appears when you successfully log into TNTAP) displays information from the taxpayer level and will show any balances or credits across all accounts. To view information specific to an account, you will need to click on that account to view the springboard for that individual account. Viewing each account will help you identify the account on which the balance exists.