DETROIT (AP) — Donald Trump paced his rally stage in silence for nearly 20 minutes Friday night in Detroit after his microphone cut out.

The Republican nominee and former president was about to wax on about one of his favorite subjects, tariffs, working up to naming it by first teasing “the most beautiful word in the dictionary.” Very quickly afterward, the sound went down.

The crowd chanted “USA” and “We love Trump” in support. But with no microphone, Trump simply wandered around the stage. Looking frustrated, his back was turned to most of his audience at times.

It was the second time in a week that one of his events was interrupted — though the last time, on Monday, Trump cut off a town hall and instead played music after multiple people in the audience needed medical attention. This time, Trump appeared to have little control over the matter, standing silently while the screens in the room displayed the messages “Technical Difficulties” and “Complicated Business.”

Trump is famously attuned to his image and the mechanics of his rallies, often commenting on the microphones and teleprompters. Earlier Friday, the hosts of “Fox & Friends” joked that Trump likes to adjust the lighting when he sits for interviews.

Aides are known to travel with multiple backup mics — though it was unclear why they weren’t able to locate one immediately Friday — and to carefully prepare the flags that decorate his stages.

As the delay stretched on, the crowd continued to cheer and chant. At one point, the crowd did the wave.

Finally, after nearly 20 minutes, an aide brought Trump a replacement microphone that worked.

“I won’t pay the bill for this stupid company,” he said. “I won’t pay the bill, and then we’ll have a story that Trump didn’t pay the bill to a contractor.”