Devices do not work with USB-C-Digital-AV-Multiport-Adapter

Hello community,

I have a Macbook 12" and as it comes with one USB-C port also the "USB-C to USB" and the "USB-C Digital AV Multiport Adapter". Interestingly my external hard drive / DVD writer work perfectly with the "USB-C to USB" but not with the multiport adapter (A1621). With the latter, the devices seem not to get enough power which is strange because it also has the port for the USB-C charging cable. Even without HDMI connected, I cannot do backups, watch DVDs while being connected to the charger.

As the multiport adapter was quite expensive I am highly disappointed as I expected to overcome the charing problem while using external devices.

I run macOS Sierra with all updates (also the one for the muliport adapter) installed.

Any ideas?

Best regards,

Michael