Your SSN has been used as a dependent's SSN on someone else's tax return.
Fix #1: Sign into your PriorTax account and double check that the name and social security number provided is valid and correct, matching what is on file with the IRS database and Social Security Administration. You can update this information from your status page and resubmit for filing.
Fix #2: If you know the taxpayer who claimed you as a dependent on their tax return already, then you can contact them directly. They have the option to amend their tax return, removing you from their list of reported dependents. You can then resubmit for filing.
TIP: The most common cause of this rejection is when the taxpayer is unaware that they are being claimed as a dependent on a parent's tax return.