There are track width settings in the overall PCB Design Rules settings as well as in the Autorouter.

You may find the answer if you compare your track width setting in the PCB Design Rule settings with the settings in the Autorouter (bear in mind the units):

There is another problem for autorouter.
Your pads are overlop the cutout, our aurtouer code maybe can not router very well. You would better to change the package or layout by your self.

@dillon: Something weird is going on here. I tried your suggestion above but it didn't make a difference. So, I created a new test PCB from the schematic and used the default settings which Auto Routed perfectly. I tried copying over the same working settings to my main board and continue to get the same error.

I'm not sure if this is bug or user error.

I think It is an EasyEDA problem for the auto router. And we spent lots of time, and can't find why.

What I changed.

1 Your PCB auto router unit is Inch, you need to input the right value for inch router, now I change to mil, I think it is easy for mil.

2. changed the new board outline, you may need to copy a new board outline and adjust.

You can save my PCB to your project and make your project done.
https://easyeda.com/support/Boomerang_Keyboard_copy-f4ced6ff971d4d09ac1a6776beb9c731