Sen. Elizabeth Warren (D-MA) participated on Monday in the Native American Presidential Forum in Sioux City, Iowa, and apologized for making “mistakes” in the past.

Warren was the second speaker out of a slew of fellow 2020 candidates slated to speak at the forum over the next two days. She told the crowd she has “listened” and “learned a lot” and offered another apology for her past “mistakes,” which involved listing herself as a minority in the Association of American Law Schools (AALS) deskbook for more than a decade. She also listed herself as a Native American on her Texas Bar registration card.

“Like anyone who’s been honest with themselves, I know that I have made mistakes,” Warren told the crowd. “I am sorry for harm I have caused.”

“I have listened and I have learned a lot, and I am grateful for the many conversations we have had together,” she added:

Warren has failed to offer a consistent explanation for her previous claims to Native American heritage.

“I listed myself directory [sic] in the hopes that might mean that I would be invited to a luncheon a group something with people who are like I am. Nothing like that ever happened. That was absolutely not the use for it and so I stopped checking it off,” Warren told reporters in 2012 during her battle with former Massachusetts Sen. Scott Brown.

“Being Native American is part of who our family is and I’m glad to tell anyone about that. I am just very proud of it,” Warren said around the same time.

She has attributed her claims to Native American heritage to her grandfather’s “high cheekbones” and has said, “Being Native American has been part of my story, I guess, since the day I was born.”

Warren’s claims fell apart last year after a DNA test revealed she had between 1/64th to 1/1,024 Native American ancestry. However, she did not appear to have connections to tribal nations in America, with her results stemming from “residents of Colombia, Mexico, and Peru,” as Breitbart News reported:

The results of that analysis, published on October 16, showed Warren may have a common ancestor who lived approximately six to 10 generations ago with residents of Colombia, Mexico, and Peru. These results mean that at the very least, Warren shares 1/1024 common DNA with residents of Colombia, Mexico, and Peru. At the very most, she shares 1/64 common DNA with residents of Colombia, Mexico, and Peru.

This is not the first time Warren has issued an apology. Cherokee Nation confirmed that the Massachusetts senator privately apologized following the results of her DNA test.

“I understand that she apologized for causing confusion on tribal sovereignty and tribal citizenship and the harm that has resulted,” Cherokee Nation spokeswoman Julie Hubbard said. “The chief and secretary of state appreciate that she has reaffirmed that she is not a Cherokee Nation citizen or a citizen of any tribal nation,” she added. Despite that, Warren has still faced questions on the campaign trail. During a “Conversation with the Candidate” event last month, an attendee asked Warren how she will “overcome the bridge with voters” who question her original decision to claim Native American heritage in years past.