The 2021 ACM Awards gave Dan + Shay, who won Duo of the Year during the show on Sunday night (April 18), plenty to celebrate; however, they also dealt with some technical difficulties during their performance. As the duo sang their new song "Glad You Exist" from Nashville's Bluebird Cafe, an audio/video sync issue occurred, causing some fans on Twitter to wonder if the duo might be lip-syncing. Rather, Dan Smyers and Shay Mooney explained backstage in the virtual ACMs press room, an audio glitch that occurred during their performance, which was pre-taped in advance of the show, caused the problem. "It's been a difficult time to put these awards show together during these crazy times, and a lot of us have had to pre-tape our performances, and that's what we did," Mooney explained. "We pre-taped it yesterday. We were super stoked about the performance."