I have the Apple MacBook 12" (2016) 1,1GHz 256GB Silver and a 4K/60Hz monitor.

I have tried this hardware to connect the displays at 4k/60Hz:

* Anker® Aluminium USB C Type C to HDMI Converter, Supports 4 K/60Hz to
HDMI Converter
* Kanaan USB-C HDMI Adapter | USB-C USB 3.1 Type-C to
HDMI Adapter Converter

This works perfectly when the USB-C port is connected directly to my MacBook.

I have only 1 USB-C port on my MacBook. 

When I add a Belkin USB-C hub or even try to use the USB-C port of the Apple Multi-AV adapter, both adapters don't work, they don't provide any video output.

I have these USB-hubs/adapters:

* Apple USB-C Digital AV Multiport Adaptor
* Belkin USB-C 4 Port Mini Port Expansion Hub

Am I missing something here? In my ideal situation I'd like to be able to connect my 4k/60hz monitor, 1440p/60hz monitor and the charging cable at the same time, but the 1440p monitor isn't that important. I'd settle with both the 4k/60hz and charging cable at the same time.