ST. PAUL — The chief of Minnesota’s health insurance marketplace resigned Tuesday after facing criticism over the troubled rollout and a questionably timed international vacation.

April Todd-Malmlov submitted her resignation during an emergency closed session of the government board of MNsure, Minnesota’s version of the insurance exchange that’s tied to the federal health care overhaul. She had been under increasing pressure over insurance sign-up problems and failed to get a vote of confidence from Democratic Gov. Mark Dayton last week.

Scott Leitz, an assistant commissioner at the state Department of Human Services with more than a decade of high-level health care experience, was named interim chief executive while a search for a permanent leader is conducted.

“MNsure must do better. If there are problems or mistakes, we will acknowledge and fix them,” Leitz said in a statement released by the agency. He was to hold a news conference today.

Dayton said he fully supports the switch and has faith in Leitz’s abilities.

“The recent problems some have experienced with MNsure are completely unacceptable. I am hopeful that this new leadership will lead to their swift resolution,” he said in a written statement.

Todd-Malmlov, 36, was not made available for comment. She was a key figure in Minnesota’s adaptation to the federal health overhaul since 2011. The exchange is meant to show people what options they have to buy subsidized health insurance. But after the Oct. 1 enrollment launch, MNsure’s website encountered technical issues and a backup call center didn’t fare much better.

Questions over Todd-Malmlov’s leadership ramped up after disclosure of an extended trip to Costa Rica in late November, as critical insurance enrollment deadlines neared and issues were unresolved.

Minnesota’s exchange has had so many technical issues that some health insurance companies expressed concerns about whether people signing up for coverage would have it starting Jan. 1.

Republican lawmakers and Dayton have voiced frustration with the situation. Last week, Dayton withheld praise for MNsure’s leaders but pointed out that only its board of directors had the direct power to remove its executive director. One of Dayton’s 2014 challengers, Scott Honour, called Monday for Todd-Malmlov to resign.

Even with her departure, Republican critics didn’t let up.

“Today’s resignation of MNsure’s executive director does not change the fact that MNsure is a fiasco,” said Ben Golnik, chairman of the Minnesota Jobs Coalition and a leading critic of Dayton’s administration.

Todd-Malmlov had led the development of Minnesota’s health insurance exchange since its formative days in early 2011. It was once under the joint control of two state agencies but is now an independent entity. The Minnesota native previously served as the state of Minnesota’s health economist and also worked for Minnetonka-based UnitedHealth Group.

Todd-Malmlov was earning an annual salary of $136,680. It wasn’t immediately clear if her departure came with a severance package.

Todd-Malmlov maintained a calm facade even as MNsure struggled to overcome technological and security glitches. A recent report by the state’s Office of the Legislative Auditor rapped MNsure leadership for oversights it said contributed to a breach earlier this year of private information belonging to Minnesota insurance agents, including Social Security numbers.

MNsure’s managers also took heat from Democratic lawmakers angry that grants to private nonprofits helping with outreach to potential MNsure customers seemed to neglect groups led by blacks and African immigrants, prompting the MNsure board of directors to quickly approve a second round of grants.

The most recent federal data put Minnesota in the middle of the pack for private insurance sign-ups under the federal health overhaul, with 4,478 policies. However, state and federal officials say the state has seen a faster pace of people signing up for Medical Assistance or MinnesotaCare, the state’s programs for low-income people and families.