Also reported on frwiki by @Olaf : https://fr.wikipedia.org/wiki/Discussion_Projet:Lingua_Libre#Lingua_Libre_not_working

Thx for reporting, i will try to check and fix it today.

Another user reported the following error 2 days ago:

Maybe it will help.

In T402546#11109851, @mickeybarber wrote:

Thx for reporting, i will try to check and fix it today.

Hi, if you don't manage to fix the issue, we can temporarily allow your traffic, if you provide us with the IPs from which we'll receive it.

Report by user:Fenakhay , using Firefox :

I can't log in to LinguaLibre:

OAuth login error: Decoding server response failed: No error (Raw response: Please set a user-agent and respect our robot policy https://w.wiki/4wJS. See also T400119. )

Another by Polish user:Olaf :

@Yug thanks, no need to keep appending user reports till @mickeybarber reports back. This is a well-known and expected behavior of the CDN as announced on https://lists.wikimedia.org/hyperkitty/list/wikitech-l@lists.wikimedia.org/thread/APW6FQBGIVLCEN7WZ65D4NVZ6XQIWGCW/ back in 2025-07-30

Thanks @Joe for your work, and I completely understand the new policy.
LinguaLibre runs on MediaWiki (1.35), and if I understand correctly, I can't change the User-Agent.
Could you please whitelist these IPs:

• 152.228.161.167
• 2001:41d0:304:100::4790

If you have a solution to fix it on a MW, please don’t hesitate to share it.

Hi @mickeybarber,

From Special:Version it appears Lingua Libre is running mediawiki/oauthclient 1.1.0. The ability to set a custom User-Agent (via Config::setUserAgent) was added in 1.2.0 (commit 81edea5f545ef551cb1fb3e8937fd81c549fa94b, task T293609).

You have two paths:

• Upgrade mediawiki/oauthclient to >= 1.2.0
• Backport just that upstream commit

After that you need to patch your local copy of OAuthAuthentication to add the custom User-Agent:

diff
diff --git a/utils/Config.php b/utils/Config.php
index d61d793..00f02d6 100644
--- a/utils/Config.php
+++ b/utils/Config.php
@@ -24,6 +24,7 @@ class Config {
                        $wgOAuthAuthenticationUrl, // url to use
                        $validateSSL // do we validate the SSL certificate? Always use 'true' in production.
                );
+               $config->setUserAgent('LinguaLibre/0.1 (https://lingualibre.org; contact@lingualibre.org)');
 
                if ( $wgOAuthAuthenticationCanonicalUrl ) {
                        $config->canonicalServerUrl = $wgOAuthAuthenticationCanonicalUrl;

Recommendation: Plan a broader MediaWiki + extensions refresh; staying on older versions increases exposure to missed security updates.

Thanks a lot @Vgutierrez,

It's fixed now.

Recommendation: Plan a broader MediaWiki + extensions refresh; staying on older versions increases exposure to missed security updates.

We are rewriting LinguaLibre, without MediaWiki behind it, but we are behind schedule :(

Thanks, everyone, for such a quick resolution!

For future reference, if a user files a bug about an extension, it would be great to either tag that extension on the ticket or file a new ticket about the particular issue in the extension. Having the user just manually patch their version of the extension's source code does nothing for all the other users of the extension. Maintainers cannot maintain extensions of bug reports are hidden from them.

In any case, I filed T402742 and submitted a patch

In T402546#11113441, @Bawolff wrote:

For future reference, if a user files a bug about an extension, it would be great to either tag that extension on the ticket or file a new ticket about the particular issue in the extension. Having the user just manually patch their version of the extension's source code does nothing for all the other users of the extension. Maintainers cannot maintain extensions of bug reports are hidden from them.

In any case, I filed T402742 and submitted a patch

Note Lingua Libre Legacy use OAuthAuthentication, which is a different extension from WSOAuth. It is unmaintained and proposed to be archived (T322969: Archive the OAuthAuthentication extension).