Error 404 – Not Found

I’m preparing a post with about 4000 words and about a dozen screen prints and all of a sudden I am getting Error 404 – Not Found after inserting my next image to the article and clicking Save Draft.

I tried creating a new test article and inserting that same image into it and Save Draft. It worked fine.

Is there a limit to the size of post I can make or the number of images I can insert? I have made bigger posts in the past with no problem.

What is the cause of the Error 404?

Thanks for your help!

Dennis