The U.S. Postal Service has been building a new system to carry out President Trump’s push to restrict mail-in voting, including an online portal for states to submit voter information before absentee ballots go into the mail. An anonymous federal official says the system was rushed and could keep ballots from reaching eligible voters on time.

As part of the ongoing legal fight over Trump’s mail voting order, a federal judge has temporarily blocked USPS from requiring states to use the portal in order to send out their mail-in ballots for the midterm election.

The Postal Service is appealing that ruling.