First, the electronic elements are not even wedged in the housing. Plug something on one side, moves everything to the other!
Same story for the different connectors, which are not firmly plugged into the case (including the power cord and the USB cable supplied with B!).
The power then clearly proves insufficient.
The supplied adapter delivers 2A, making it very very fair for a Hub 7 ... (normally 500 mA per port)
This hub, for example, can not feed my Raspberry Pi (700 mA) and an external hard drive (1 A).
Last but not least, the hard drive that I was planning to use with is not recognized when I connect via this hub ...
Avoid it, then!