[Resolved] Customizer String not translated

Thank you for providing the information.

I have made the following config for translating penci_404_sub_heading and added it to the WPML → Settings → Custom XML Configuration:

<wpml-config>
  <admin-texts>
    <key name="theme_mods_pennews-child">
      <key name="penci_404_sub_heading" />
    </key>
  </admin-texts>
</wpml-config>

More information:
https://wpml.org/documentation/support/language-configuration-files/

Now, you can translate it in WPML → String Translation.

The text wasn’t available in Admin Texts or registered in WPML.

If you can’t find it there, you need to register it manually by creating a configuration for the relevant theme option.

Here’s an outline of the steps:
1. Go to your database and open the wp_options table.
2. Find the option with the name theme_mods_pennews-child.
3. In the option value, locate the key that stores the text you want to translate.
4. In your case, this key is penci_404_sub_heading.
5. Using the following documentation:
https://wpml.org/documentation/support/language-configuration-files/translate-strings-in-wp-options-table/
I created this configuration as an example and added it to WPML → Settings → Custom XML Configuration on your site:

<wpml-config>
  <admin-texts>
    <key name="theme_mods_pennews-child">
      <key name="penci_404_sub_heading" />
    </key>
  </admin-texts>
</wpml-config>

6. After adding this configuration, the option became registered and is now available for translation in WPML → String Translation.

I have looked at this, but I do not see the appropriate reason why the translations do not appear.

I want to ask you about the possibility of replicating your site locally. I'll need to install a "Duplicator" temporarily or "All In One Migration" plugin on your site. This will allow me to create a copy of your site and your content. If you prefer to do it independently, you can provide the snapshot and send me the zipped package you downloaded.

Let me know how you feel about this.

Thank you for your patience.

I’ve investigated this further, and it turns out that this specific translation isn't being displayed due to a theme compatibility issue.

As a workaround, I added the following code to your child theme’s functions.php file to ensure the string is correctly translated:

add_filter( 'theme_mod_penci_404_sub_heading', function ( $value ) {
    return apply_filters( 'wpml_translate_single_string', $value, 'admin_texts_theme_mods_pennews-child', '[theme_mods_pennews-child]penci_404_sub_heading' );
}, 20 ); 

I’ve also shared this information with our team so they can forward it to the theme author.