Check it is the chip's output voltage 0 or the impedance 0. If the chip's output voltage is 0, check wheter there is output in the front domain, or there is coupling capacitor falling. and there will be no CLK in the next domain; If the impedance is 0, the chip's CLK signal is short-circuited, and you need to remove one of the chips in the domain to know which chip is shorted.