In general yes, if your application status is either Pending or Rejected and you are a nonresident for tax purposes. If your Green Card has been Approved during the tax year you're preparing your return for, you cannot use Sprintax.
If you have been a Green Card holder in the past and you have already given up your Green Card and are deemed as a nonresident for US tax purposes, you might also be able to file with us.
We would recommend to report all your visits in Step 1 Residency and if you are deemed a resident for tax purposes, you will not be able to use Sprintax, and in such case you can use the services of Turbotax.