Panasonic Holdings is postponing the full-scale launch of its new electric vehicle battery plant in Kansas, according to Nikkei. The reason — a slowdown in sales at its main customer, Tesla.

Originally, Panasonic aimed to reach a production capacity of 30 gigawatt-hours by March 2027, but that target has now been delayed indefinitely. The final date for full operations has yet to be determined, the Japanese business daily reported.

The Kansas facility, which cost $4 billion to build, will be Panasonic’s second large-scale battery plant in the U.S., following its Nevada factory. Mass production is expected to begin soon.

Tesla, Panasonic’s key client, is facing multiple challenges — from declining sales due to an aging vehicle lineup, to the loss of U.S. EV tax credits and a public spat between CEO Elon Musk and former President Donald Trump.

Panasonic has so far declined to comment on when the plant might reach full capacity.