*Newbie* USB controllers not recognized on initial bootup

[Palafox2step]

Guys, trying to get this project going; installing Retropie on a Pi Zero. System boots up and gets to emulation screen and asks to hold down a button on USB controller. System won't do anything else.

I've verified that the hub and controllers work on a PC.

THANKS

PI Zero 1.3
RetroPie 4.1
5v-2a power supply
2-USB gamepads
powered USB Hub
HDMI

[Palafox2step]

@Palafox2step

I've tried plugging one controller in directly without the hub ... no luck.
Building the pi-cart in a NES cartridge for my Dad for Christmas.

[meleu]

@Palafox2step
When emulationstation shows a subwindow asking to hold down a button to configre, it also shows the number of plugged controllers. How many controllers appears for you?

[Palafox2step]

@meleu WELCOME screen shows NO GAMEPADS DETECTED ... Tried startup twice once using the hub with both controllers plugged in and then once with just the one controller plugged in without the hub.

[Palafox2step]

@Palafox2step
This is really getting frustrating. Everything I read says the system should autorecognize the controllers on initial startup.
The WELCOME screen in Emulation Station says "No GamePads Detected".
I've reloaded Retropie, tried an earlier version, plugged one controller without USB hub, tested all cables on another device.
Any additional suggestions?

[BuZz]

Which usb port are you putting the power / controller in ?

[Palafox2step]

@BuZz

Ok @BuZz you're brilliant. Changed power to other USB & now it works.

Thank you to all that helped!