According to an analytical article that Duowei News published, the delegate who Xi Jinping sent to North Korea returned back to Beijing on November 20. There are four possible reasons for Kim Jong-un not meeting with Xi’s delegate.
1) Japanese Nikkei reported that, according to an anonymous source, the first reason that Kim Jong-un took a stance against meeting the delegate was because the level of the delegate was too low; the second was because China cooperates with the U.S. and the United Nations to exercise economic sanctions against North Korea.
2) Another analysis suggested that Kim Jong-un was extremely upset that Xi’s delegate visited Vietnam and Laos first before coming to North Korea. In the past, the Chinese delegate would always visit North Korea before visiting other countries. Kim Jong-un was also unable to accept the fact that Xi Jinping extended warm hospitality toward Trump during his visit while Kim only received a letter from Xi. As of that time, the leaders of these two countries had never officially met.
3) The media from China and North Korea had different coverage about the visit. North Korean media reported that Xi’s delegate offered a gift to Kim Jong-un but Kim Jong-un did not accept it. Also, the delegate had a dinner banquet with high ranking officials from North Korea during the visit. China’s official media did not report any of this.
4) An article that China’s mouthpiece, Huanqiu, published on November 18 suggested that people shouldn’t have high expectations for this visit. According to the article, “The delegate is not a magician. … He simply helped by knocking on the door so it would open, but it could close at any time.”
Source: Duowei News, November 21, 2017