No sound from Ibanez TOD10N into Boss RC-505 MKII (but works fine with amp)

Hi everyone — looking for help with a strange issue.

My Ibanez TOD10N (electro-acoustic with built-in preamp) works perfectly when I plug it directly into a regular guitar amp, so the guitar and cables seem fine. However, when I plug the same guitar into the INST input of my Boss RC-505 MKII using a standard 1/4" instrument cable, I get absolutely no guitar sound — nothing at all through speakers or headphones connected to the looper. The only thing I can hear is a tiny click when I press the tuner button on the guitar, which suggests the looper receives some kind of reaction from the guitar electronics, but it doesn’t transmit the actual audio signal.

I’ve already confirmed: correct input selected on the RC-505 MKII, input/output levels not muted, routing checked, and the guitar’s onboard preamp powered via battery since it works on an amp.

The problem appears only when using the RC-505 MKII as the input device and disappears completely when using an amp.

If anyone has experienced something similar with the RC-505 (especially with electro-acoustic or piezo systems) or has general suggestions, troubleshooting ideas, or setup recommendations I might have missed, I’d really appreciate any advice.

Sorry if it's the wrong sub to ask this question.