A Massachusetts-based election equipment manufacturer is giving up for now on selling its machines to North Carolina counties.

Clear Ballot’s chief executive told the State Board of Elections it was withdrawing its request to certify its recent product upgrades.

CEO Jordan Esten’s letter last week blamed the board’s slow pace for its troubles, saying the company was unable to communicate with the state’s counties during the two-year wait for the original certification. Esten said that gave current dominant equipment manufacturer Election Systems & Software “a marketing monopoly in the state.”

“We still want to work with North Carolina,” Esten wrote. “However, the environment and rules continue to stifle competition, which is regretfully causing us to withdraw our certification request at this time.”

The board has been in flux over the past few years as the legislature reworked the panel’s makeup and Democratic Gov. Roy Cooper challenged those changes in court.

Equipment by Omaha, Nebraska-based ES&S, Clear Ballot and Hart InterCivic of Austin, Texas, had been certified by the state board in August. The state board voted 3-2 on Dec. 13 to accept upgrades by ES&S but didn’t address Clear Ballot’s request.

Only Onslow County had expressed strong interest in using Clear Ballot machines and tested them during the November municipal primaries. The Onslow County elections board will now test voting systems by Hart InterCivic in one precinct during the March primary, state board spokesman Pat Gannon said Monday. Clear Ballot also had balked at the large bond that state law required the company to post, board general counsel Katelyn Love told board members last week in an email.

Voting equipment can’t be sold to the state’s 100 counties unless the board approves its use. State law now bars touchscreen-only voting equipment from being used in North Carolina. About 20 counties with such machines have to find replacements. Gannon said Onslow County for now will keep using its ES&S optical scan machines, which count paper ballots. That equipment is still certified.

Voting equipment also has received more attention and scrutiny nationwide after hackers tried to access U.S. election systems in 2016.