Hi,
Thanks for posting this question.
Fusion is designed to avoid circular dependencies, but, it appears you have found a way that is not protected. Basically, it's saying that the sketch is referring to a plane that refers to the sketch. This might have happened when you reordered features in the timeline.
There are a couple things you could try.
First, open an older saved version of the design, from before the creation of the circular dependency. Continue working with the design and avoid the steps that cause a new circular dependency. Help article explaining how to do this.
Tip: read the error messages when they appear, and take note of red or yellow warnings in the timeline. Those are indicators that the action you took caused loss of references, or other parametric errors. Stopping and understanding why some action resulted in an error/warning is a critical step for you, when it happens.
Here is an Autodesk University class that explains this part of Fusion.

If an older version of the file is not usable, try converting the work plane into a DM feature. This removes the parametric dependencies and seems to revive your design somewhat. There are red and yellow features in the timeline, but I have no idea if those existed prior to the circular dependency.

Phil Eichmiller
Software Engineer
Quality Assurance
Autodesk, Inc.