Elementor sends page data to the server with an AJAX request. The request includes a security nonce and a JSON payload that describes every widget and setting. If the server rejects the request or the script stops, Elementor shows a red toast and never finishes the save.
The failure may happen because the server runs out of memory, hits execution limits, or lacks permission to write files. It also occurs when another script interferes with the AJAX call or when the nonce expires after a long editing session.
The error appears most often after a WordPress or Elementor update, on low‑resource hosting plans, or when a page contains many sections and widgets. Large pages increase the size of the JSON payload and stress server limits.