Lady Gaga has postponed her Mayhem Ball concert in Miami due to vocal issues. The singer, 39, was to perform at Miami's Kaseya Center on Wednesday, September 3, at 8 p.m. ET. She announced the postponement via her Instagram Stories that night. "Hi everyone I am really so so sorry," she wrote, "but I need to postpone tonight's show in Miami." Gaga explained, "During rehearsal last night and my vocal warmup tonight my voice was extremely strained and my Dr and my vocal coach have advised me not to go on because of the risk it poses.