Per our updates, the Form D-40B is available for print or mail-in, but not for e-file. When you filed both of your federal and state tax returns, this form did not go through e-file. You would need to print it out and submit by mail to the State of District of Columbia. Click here: State tax forms availability
To see more information on this form and where to mail, click here form D-40B and read page 2.
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