BERLIN (Reuters) - Irish rockers U2 canceled a concert in Berlin on Saturday after frontman Bono lost his voice a few songs into the show. FILE PHOTO - Bono of U2 performs during the band's "Experience + Innocence" tour at The Forum in Inglewood, California, U.S., May 16, 2018. A video recorded by a fan and posted on Twitter showed Bono interrupting proceedings there on Saturday and telling fans in a hoarse voice: “I’m so sorry. I’m sure this is not a big problem but I’m gonna have to do something.”