A software error caused baggage screening machines at the Portland International Jetport to shut down Monday morning, leading to flight delays and nearly 200 bags being left off planes.

The problem began shortly before 5 a.m., when three explosives detection machines that screen checked bags indicated they would no longer accept luggage for screening, said Paul Bradbury, the airport’s director. That meant that Transportation Security Administration workers had to manually screen all the checked luggage by opening and inspecting each bag, Bradbury said.

“It’s a Herculean effort,” he said, but some flights were delayed and 194 bags weren’t loaded on their flights. Normally, 95 percent of checked baggage is cleared by the machines, he said, and only 5 percent require a manual check.

The problem was fixed shortly before 7 a.m. after a TSA technician arrived and got the machines working again, Bradbury said.

The longest delay was nearly an hour on a Delta flight to Atlanta, he said, and 58 bags weren’t loaded on a Southwest flight to Baltimore. The cumulative delays attributed to the baggage handling issue was almost four-and-a-half hours, Bradbury said.

The problem occurred during one of the busiest times of the day at the airport, Bradbury said, with many outbound flights scheduled between 5:45 a.m. and 7 a.m. The TSA had to pull workers from their passenger screening stations to check the luggage, resulting in delays in that operation, he said.

Bradbury said the airlines are working to try to reconnect passengers with their luggage. Flight operations were back to normal by midmorning, he said.