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This thread is resolved. Here is a description of the problem and solution.

Problem:
You are trying to install WPML but are encountering a blank setup page along with a JavaScript error in the browser console, specifically 'Uncaught TypeError: l is undefined'.
Solution:
We recommend enabling debugging to identify the underlying issues. Here’s how you can do it:
1. Open your site’s

wp-config.php

file.
2. Locate the line

define('WP_DEBUG', false);

and change it to:

define('WP_DEBUG', true);

3. To log these errors to a file, add:

define('WP_DEBUG_LOG', true);

This will save the errors to a debug.log file in your /wp-content/ directory.
For more detailed instructions, visit our debugging documentation at https://wpml.org/documentation/support/debugging-wpml/.

If this solution does not resolve your issue or seems irrelevant due to being outdated or not applicable to your case, we highly recommend checking related known issues at https://wpml.org/known-issues/, verifying the version of the permanent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. If you still need assistance, please open a new support ticket at WPML support forum.

This is the technical support forum for WPML - the multilingual WordPress plugin.

Everyone can read, but only WPML clients can post here. WPML team is replying on the forum 6 days per week, 22 hours per day.

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This topic contains 1 reply, has 0 voices.

Last updated by Andrey 11 months, 3 weeks ago.

Assisted by: Andrey.

Author Posts
April 30, 2025 at 6:48 am #16981780

stephanieS-33

Background of the issue:
I am trying to install WPML but I am receiving a blank setup page. There is a JavaScript error in the browser console, and I can't proceed with the installation from this state.

Symptoms:
Blank setup page and JavaScript error in the app.js: Uncaught TypeError: l is undefined.

Questions:
What causes a blank setup page during WPML installation?
How can I resolve the JavaScript error: Uncaught TypeError: l is undefined?

April 30, 2025 at 1:43 pm #16984277

Andrey
WPML Supporter since 06/2013

Languages: English (English ) Russian (Русский )

Timezone: Europe/Kyiv (GMT+03:00)

Thank you for contacting WPML support.

Have you tried enabling debugging to see if there are any errors?

You can add a few lines to the site’s wp-config.php file. With the error log enabled, you will see the actual problem.

To enable it, open your wp-config.php file and look for define('WP_DEBUG', false);. Change it to:

define('WP_DEBUG', true);

To enable the error logging to a file on the server, you need to add yet one more similar line:

define( 'WP_DEBUG_LOG', true );

The errors will be saved to a debug.log file inside the /wp-content/directory.

https://wpml.org/documentation/support/debugging-wpml/

Let me know what you see after the debug mode has been enabled.