“CBS Evening News” anchor Tony Dokoupil is broadcasting from Taipei, Taiwan, this week — after the network failed to obtain a visa for Beijing where President Trump is meeting with his Chinese counterpart Xi Jinping , a misstep that sources called “very sloppy” and “stupid.” CBS News’ “poor planning” left the network scrambling to get Dokoupil to China’s capital, where his rivals Tom Llamas of NBC News and David Muir of ABC News are on the ground for anchor duties. CBS News editor in chief Bari Weiss wanted to get Dokoupil to Beijing after learning Muir would be there, but it was “too late” to obtain the press visa for him, said a source with knowledge of the matter. The Taiwan trip took shape after that. “CBS Evening News'” Tony Dokoupil will anchor from Taipei after CBS News failed to secure a Chinese visa in time. CBS via Getty Images CBS News declined to comment to The Post.…