Their bad. Grammys producer Ken Ehrlich issued an apology to Metallica on behalf of the Grammys crew for the “awful” technical difficulties that went down at the 2017 Grammys on Sunday, February 12. (Relive the technically flawed performance in the video above.)

On Sunday, lead singer James Hetfield’s mic didn’t appear to be working for the first portion of Metallica’s performance with Lady Gaga, leading the veteran rocker to share Gaga’s mic. Metallica drummer Lars Ulrich later revealed during a Tuesday interview with James Corden that Hetfield was “livid” over the incident.

“I haven’t seen him like that in 20 years,” Ulrich, 53, told the Late Late Show host. “I mean, he was livid. I mean, he’s aged really well and he’s a pretty chill guy, but the first five or 10 minutes in that dressing room [were] not a lot of fun.”

In response, Ehrlich said he was taking responsibility for the snafu. “Obviously, we apologize to the band,” Ehrlich told the Associated Press on Wednesday, February 15, calling the mishap “awful.” The longtime producer added that the mistake was especially affecting because he had worked with the band for many years prior. “You hurt,” he said.

Though Metallica blamed the glitch on a dead microphone, Ehrlich said he heard it was more a matter of human error. “My guys say that the mic cable was connected,” he told the AP. “My guys’ theory was that … one of the extras [on stage] accidentally kicked out the cable that went to the mic.”

In addition to Metallica’s mic troubles, the show also had a minor hiccup when Adele asked to restart her tribute to George Michael, for which she publicly apologized to Ehrlich. “I know it’s live TV … I’m sorry for swearing, and I’m sorry for starting again,” she said onstage about one minute into her slowed-down performance of Michael’s hit “Fastlove, Part 1.” “I can’t mess this up for him.” She went on to flawlessly belt out his 1996 tune.

“When you do a three-and-a-half hour live show, it’s fraught with danger,” Ehrlich summed up to the AP. “It was an adventurous show in many ways.”

Sign up now for the Us Weekly newsletter to get breaking celebrity news, hot pics and more delivered straight to your inbox!