[Resolved] Random 404 errors on non-default language pages

Hi,

Thank you for contacting WPML Support. Thanks for the video, I can see the issue on your site. This type of issue usually arises due to some third party plugins when they call flush_rewrite_rules(true) function too often and it can only be fixed directly by the plugin author.

As a quick workaround, could you please try to follow the below steps and see if this resolves your issue:

1. Please take a backup of your site first for safety reasons.

2. Add the below code in the functions.php file of your theme:

add_filter('mod_rewrite_rules', 'fix_rewritebase');
function fix_rewritebase($rules){
    $home_root = parse_url(home_url());
    if ( isset( $home_root['path'] ) ) {
        $home_root = trailingslashit($home_root['path']);
    } else {
        $home_root = '/';
    }
  
    $wpml_root = parse_url(get_option('home'));
    if ( isset( $wpml_root['path'] ) ) {
        $wpml_root = trailingslashit($wpml_root['path']);
    } else {
        $wpml_root = '/';
    }
  
    $rules = str_replace("RewriteBase $home_root", "RewriteBase $wpml_root", $rules);
    $rules = str_replace("RewriteRule . $home_root", "RewriteRule . $wpml_root", $rules);
  
    return $rules;
}

3. Re-save the permalinks from the Settings >> Permalinks page by pressing the Save Changes button.

4. Delete all sorts of caches on your site/server cache if any / plugin cache / CDN cache, clear the browser cache, and then see if it resolves the issue afterward.

Here you can see more details about it:
https://wpml.org/faq/why-is-htaccess-getting-overwritten-with-the-language-folder-on-my-wpml-website/

Please let me know the results,
Thank you for your cooperation

That sounds good. Please take your time to test it over the next few days, and let us know if the issue appears again.

Thank you