editor disappeared

The button in the editor’s window was missing, and the editor also disappeared. I have 2 sites on the same domain, they are technically similar. On first site – plug-in broke, on the second site – it still works. But there are fears that there too will break. You have to find the reason or go to the beaver before it’s too late. Beaver works great everywhere. The Origin are easier to manage, but I need something working …