What problem made China reluctant to improve relations with the United State?

The main problem that made China reluctant to improve relations with the United States was the issue of Taiwan. Taiwan, officially known as the Republic of China, is considered by China to be a province that is rightfully part of its territory. However, Taiwan is a self-governing island that has its own government and constitution, and it has never been under direct control of the People's Republic of China (PRC) since its founding in 1949.

The United States has long been a supporter of Taiwan, and it has provided military and economic support to the island. This support has been a source of tension between the United States and China, as China views it as interference in its internal affairs and a violation of its sovereignty.

In recent years, tensions between China and the United States over Taiwan have increased, as China has stepped up its military presence around the island and has asserted its territorial claims more forcefully. This has led to concerns about the potential for conflict between the two countries.

The United States and China have also had disagreements over a number of other issues, including trade, human rights, and cyber security. These disagreements have further complicated the relationship between the two countries and have made it difficult for them to work together on common challenges.