SD Card slot on MacBook pro not working

My SD Card slot on my MacBook pro early 2015 is not working. I plugged it directly into the mac, but it did not show up on my device. This is a card that has files on it; and i have used in the very same slot successfully before. However, when i put the card in a USB card reader, and plug it in my mac...

it works!

Incidentally, a notification came up on my device a couple days ago that read:

'USB Accessories Disabled

Unplug the accessory using

too much power to re-enable

USB devices'

I didn't pay much attention to it, because i had nothing plugged in except a regular headphone (s).

I'm not sure if that caused anything, or what it meant.

Still don't know!

Does anyone have any ideas on why my sd card slot could be out,

or why I got that 'strange' notification.

Thanks

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