NRF52840 i2s output example NCS 2.7.0 no data

Hi,

I'm trying to run the i2s output sample from NRF Connect SDK 2.7.0 on the nrf52840 DK, and I'm only getting the clock signal from P1.15, and no signal from any of the other lines (SDIN, SDOUT, LRCK).

My code is basically unmodified from the sample:

The only change I did was change DEVICE_DT_GET(DT_ALIAS(i2s_tx)); to DEVICE_DT_GET(DT_NODELABEL(i2s_tx));

The only other change I did was add an app.overlay:

The pink signal is I2S_SCK, teal is SDOUT, blue is SDIN. With the exception of I2S_SCK the other signals are basically zero.