More than 10,000 absentee ballot envelopes sent to voters by the Board of Elections in the nation's capital did not feature a reminder to include stamps.
The envelopes usually have an "additional postage required" box for stamps, but the lack of a reminder is causing confusion, The Washington Post reports.
Board spokeswoman Rachel Coll says the reminder box wasn't included on the sample envelope that was submitted to a printer, and the agency can't reprint envelopes before Election Day.
The U.S. Postal Service says it will deliver ballots with insufficient postage and just charge the local elections agency. Postage for an absentee ballot is a single Forever stamp, and the ballots also can be dropped off at the Board of Elections' office.