Problem: If you're experiencing a 500 error when trying to copy content into a translation using the 'copy_from_original' AJAX call, it might be due to the function attempting to select distinct from all meta fields in a site with many post meta, which leads to the error. Solution: We recommend modifying the code to add a filter by post_id in the function that selects meta fields. This change should help in reducing the load and preventing the 500 error. For detailed steps on how to implement this, please refer to our forum post: https://wpml.org/forums/topic/syncing-custom-fields-performance-issues/#post-15258092.
If this solution does not resolve your issue or seems irrelevant due to being outdated or not applicable to your case, we highly recommend checking related known issues at https://wpml.org/known-issues/, verifying the version of the permanent fix, and confirming that you have installed the latest versions of themes and plugins. Additionally, you can open a new support ticket for further assistance at WPML support forum.
