DC Infrastructure in a Nutshell
When trying to submit payment for a parking ticket that's due within 30 days using the DC DMV website:
We are unable to process your payment at this time. It may take up to 20 days to post a ticket to this system. To pay the fine, you may either try our online system later, mail a check or money order, payable to the D.C. Treasurer, to Adjudication Services, P.O. Box 2014, Washington, D.C. 20013 or you may pay in person Monday-Friday between the hours of 8am - 5pm at 301 C Street, NW, Room 1140. Write your tag and driver's license number on your check or money order.
No further explanation needed.