OREGON CITY, Ore. (AP) — Problems with a ballot sorting machine are slowing vote counting in a suburban Portland county that was also plagued by counting problems in 2022 and is hosting this year a key congressional race.

The sorter in Clackamas, Oregon’s third-largest county, began experiencing mechanical problems about a week after ballots were mailed to voters in mid-October, elections officials said Thursday.

Sometimes the movement of ballots stops abruptly, making it difficult to process a large volume without interruption. The problem also delayed voters’ ability to know whether their ballots were counted, officials said.

Representatives from the company that manufactured the sorter were on hand to attempt to repair it.

County Clerk Catherine McMullen, elected in 2022, told The Oregonian/OregonLive As of Wednesday, ballot processing was “about a day behind where we want to be.”

Clackamas County makes up a large part of U.S. District 5, considered one of the closest races in the country as a Republican incumbent seeks to fill a seat she narrowly edged out from Democrats in 2022.