Boeing has terminated an agreement to join forces with Brazilian jet maker Embraer.

The pair had planned to work together on Embraer’s commercial aviation business and to develop new markets for its C-390 Millennium aircraft. They had been working toward an agreement for two years.

Embraer had historically been a leading rival to Montreal-based Bombardier Inc., which has now sold or agreed to sell its C Series and CRJ commercial jet business units to Airbus and Mitsubishi.

Boeing and Embraer announced their planned partnership in July 2018, shortly after Bombardier agreed to sell a majority stake in its C Series program to Airbus.

Boeing says Embraer did not meet conditions laid out by their deal.

The Chicago-based aircraft manufacturer would have held majority ownership in the joint venture. The abandoned deal had placed the value of the new company at more than $4 billion.

The collapse marked the latest mishap for Boeing. The company’s bestselling plane, the 737 Max, has been grounded for more than a year after two deadly crashes that led to federal investigations. Those problems, combined with deflated demand for flights due to the pandemic, sharply reduced the company’s cash.