Essentially, circa 2015+, Australia began loudly pushing back on Chinese claims to the South China Sea & regarding Taiwan, and banned Huawei involvement in core telecom.

China, seeking to make an example in the region, escalated.

https://www.hudson.org/research/17228-how-china-overreached-...

"Since 2018, China has refused to accept cabinet-level meetings with Australian counterparts, and for the past year is refusing to even accept phone calls. Since 2020, Beijing has imposed punitive measures against Australian barley, coal, timber, beef, cotton, sugar, copper, wool, lobsters, wine, and liquefied natural gas. These export sectors bring in around $15 billion a year from China. State authorities have issued arbitrary travel and safety warnings to Chinese students hoping to study in Australia."