Arduino Doesn't Work on External Power

My code compiles and runs perfectly when connected to a computer but when it is connected to external power it doesn't run right. I am using a power bank as a power source so it is still getting power through usb. The LED matrix lights up and is getting power but none of the controls work. It acts as though none of the controls are connected. The second that its plugged back into the computer it work correctly though

Usually weird stuff like that is caused by ground wires not connected in your circuit where grounds are required. So, check your wiring and make sure any required grounds are connected, such as to your controls. Without seeing a schematic of your circuit and clear photos of your neat wiring, we can't tell for sure.

I've since plug it into a wall adapter and now it only works on the wall adapter and not on the computer anymore. Could it be an issue with my board?

I don't know. It sounds like bad wiring to me. If it works ok some of the time, the board itself is probably OK.

Here is a video of it. As you can see it quite literally stops taking input from the buttons after switching power sources. I've checked all of the connections and they seem to be fine and I don't change the wiring while switching power sources. - YouTube

Basically every time I introduce a new power source it stops working on any of the other power sources.

I don't have any additional ideas. I can't tell without actually being there to inspect your wiring or circuit. Perhaps someone else will have some ideas.