Bruno Mars accept the award for record of the year for “Uptown Funk” at the 58th annual Grammy Awards on Monday, Feb. 15, 2016, in Los Angeles. (AP Photo)
"The piano mics fell onto the piano strings, that's what the guitar sound was. It made it sound out of tune," Adele tweeted. "(Expletive) happens."
A spokesperson for CBS, where the Grammys aired, said "there was a brief 5-8 second technical issue that was out of our control."
Justin Bieber started "Love Yourself" on guitar in good form, but ended with a vocal struggle. Little Big Town and Demi Lovato, however, had shining moments during their performances, hitting impressive and smooth high notes.
But Bieber also had a shining moment: He won his first Grammy on Monday night for best dance recording for "Where Are U Now" with Skrillex and Diplo.