Just in case you’re using Mailgun with Mediawiki…

The docs don’t cover this, but the steps in this post got it working for me:

  1. Install composer apt-get install composer
  2. Run composer update from the extensions/Mailgun folder
  3. Run php maintainence/rebuildLocalizationCache.php from the main mediawiki folder.

Running your own services get you into all sorts of fun trouble like this.