The dependent claimed on your return has already been claimed for the indicated tax year on a different accepted tax return.
Fix #1: You can remove this dependent from your return and resubmit for filing. Sign into your PriorTax account and make the change right from your rejection status page.
Fix #2: Sign into your account and double check that the information you entered for your dependent is correct. If not, you can make the necessary changes from the rejection status page of your account.
Fix #3: Do you think that your dependent was claimed fraudulently? You may need to paperfile your return. Contact the IRS at 800-829-1040.