The headset microphone needs plug-in-power (sometimes shortened to pip). The most convenient way I know of is to get a XLR phantom power to pip connector. The lowest price I know of is the Rode VXLR+ (Note: the VXLR without plus does not deliver power to the microphone and does not help). The mixer outputs 48 V phantom, the plug converts it to the pip voltage (around 5 V or so) and passes through the mic signal.
And no, a normal DI box will not help.
There are probably alternatives out there on the net. The microphone needs a few volts of power to work, as given to it from the pip system. You could build a box to do that quite easily: it takes only a battery and a few cheap and simple components. If you search the typical Chinese web pages for electronics, it ought to show up.