People are facing long waits and error messages on a ticket site as they try to get passes to the Smithsonian's new National Museum of African American History and Culture.
The museum has planned to begin online distribution Monday of more timed-entry passes for the first three months of 2017.
The Smithsonian has tweeted that it's looking into the problem.
The Smithsonian began offering passes in late August for opening day and beyond, but by the time of the museum's dedication ceremony on Sept. 24, passes for all the available timeslots had already been distributed.
A limited number of same-day passes are available first-come, first-served at the museum.