Coachella

The festival said: "She sends her sincerest apologies, and looks forward to performing at Coachella in the future."

Solange was due to play on 13 and 20 April at the event in California that's known for its A-list guests and huge artists.

Last year she made a stage appearance during her sister Beyonce's iconic set.

This year's headliners are Childish Gambino, Tame Impala and Ariana Grande.

Acts like Diplo, Billie Eilish and The 1975 will also be performing.

The band faced complete sound failures along with episodes of audio feedback.

"Can you actually hear me now?" Thom Yorke asked crowds when he returned to the stage for the second time.

"I'd love to tell you a joke, lighten the mood, something like that. But this is Radiohead..."

The live stream audio was also affected by sound problems.

The first sound drop-out occurred during Ful Stop, reports Pitchfork.