I had removed a node from my incus cluster. I decided later to add it again and it failed. I reinstalled incus on this member node in hopes that I could add it as a member again.
You need to create a fresh join token each time you attempt a join (they are one time passwords).
Aside: the critical error message is truncated in your image. In future, if you could copy-paste plain text, instead of a screen image, that would be much easier to read. Using markdown, you can put three backticks (```)on a line of their own, before and after the text you have pasted, to ensure it renders properly.