Issues with Blackmagic Bidirectional HDMI to SDI Converter

I recently bought a Blackmagic bidirectional HDMI to SDI converter to connect a laptop (via HDMI) to an ATEM Production 4K switcher. Other things are connected to the switcher that works ok. Despite trying several approaches and ensuring that everything is connected correctly, I'm still not getting any output from the SDI part of the switcher. I've even downloaded the utility for the device, but no luck so far. If i connect a monitor to the HDMI out it works fine, but i need the SDI to work for the swither. Could anyone suggest what might be causing this issue or how to troubleshoot it?

it must work .. whats your wiring ?

We use an ATEM 1M/E Production Studio 4K and for that one there are no scalers. If the one you have works the same then if you aren’t set to 50 or 60fps (as presumably that’s what the laptop is outputting) it won’t show up in the ATEM. Try setting your ATEM project to match the rate of the laptop and see if it pops into view?

Both Production Studio 4K models that I’m aware of also have at least one native HDMI input - have you tried plugging the laptop into that directly and do you get different results that with the converter or the same? Similarly do you have another HDMI source (set to the ATEM project rate) to plug into the converter and see if that shows up? Basically I know the one I work with is pretty fussy about input resolution and frame rate so chances are it’s not the converter that’s the problem (unless you’ve eliminated all other culprits)