I am in the same situation. Temporary solution was the connection TX<>TX and RX<>RX which is against the logic of UART communication. However, it worked for a couple of minutes and became unavailable. So I switched the wires to RX<>TX TX<>RX and it popped up for another couple of minutes. After that, I was never able to compile it again without the message you have in your log: Component ld2420 is marked as FAILED.
Is your sensor working without troubles?