Pretty simple. Whenever I press the "Edit Label" link it pulls up an empty space. Reloading does nothing, and neither does switching devices or browsers.
Simply open Manuscrips and go to change the label on whatever content is there. If you go to the "Edit Labels" link at the very bottom, you'll see that selecting it brings you to an empty page.
Hey, while I can see the problem on your side, I cannot personally reproduce this. While I investigate what's causing this issue, the workaround you can use is selecting the Manuscript title on the left side and then click on Labels which should have the list of colored labels.