Dear Community

I have an active USB hub (TP-Link UH700 - can't find the version, eventually V3.0), an iPhone 13 mini (iOS 15.3.1) and an iMac (macOS Monterey 12.2.1). The iPhone is connected to one of the 1.5A ports.

• When the iMac is switched on, the iPhone connects to the hub and charges without any problems.
• When the iMac is switched off, the iPhone does not charge via the hub (hub LED is on, so it has power). 
• If the iPhone is connected to the hub with the iMac switched on and charging, and I switch off the iMac with the iPhone plugged in, it continues to charge. However, when I unplug it and plug it back in, it no longer charges.
• The same phenomenon, by the way, with an iPhone 7, iPhone 11, iPhone SE or AirPods ...
• A Plantronics headset, which is connected to the same hub, charges perfectly even when the iMac is switched off - it only seems to affect Apple products.

I bought the active USB hub especially to be able to charge the iPhone even when the iMac is switched off. I can't find anything in my research that goes in this direction. But it can hardly be that this problem is unique to me.

What can I do now?

Thank you very much for your support!