If only half of the connections one uses ok

I have at times purchased the unit when I more than 3 devices are connected. Now all 6 connections are occupied. 2 x iPad, iPhone 2 x, 1 x SmartWatch, 1 x Bluetooth headset. Even if all the devices only need trickle charge and only an iPad really needs to be loaded, only the anchor device is hot and the iPad remains empty. If you use it on the device even drops the charge level. I let you know when I've found something useful.