Elementor attempts to duplicate a page by sending the entire layout as a JSON payload to the REST endpoint /wp-json/elementor/v1/copy. The server processes the request, creates a new post record, and copies the associated meta data.
If PHP runs out of memory while serialising the layout, the script aborts and returns a 500 response. The same outcome occurs when the execution time limit is reached because the page contains many sections or complex widgets.
Security modules such as ModSecurity inspect the request body. A large JSON payload may match a rule that flags it as malicious, and the firewall terminates the request with a 500 status.
When the serialized data exceeds MySQL row size limits or contains invalid characters, the INSERT or UPDATE operation fails. The database error propagates as a fatal PHP error, which also results in a 500 response.
Other plugins or the active theme may hook into the copy request, alter the response, or trigger a fatal error. Those conflicts produce the same generic server error in Elementor.