--- a/classes/Language.php
+++ b/classes/Language.php
@@ -1235,6 +1235,12 @@
      */
     public static function downloadXLFLanguagePack($locale, &$errors = [], $type = self::PACK_TYPE_SYMFONY)
     {
+        // EduBox: if the translation pack is already present in the image,
+        // do not try to download it (agents may be offline).
+        if (static::translationPackIsInCache($locale, $type)) {
+            return true;
+        }
+
         $file = self::getPathToCachedTranslationPack($locale, $type);
         $url = (self::PACK_TYPE_EMAILS === $type) ? self::EMAILS_LANGUAGE_PACK_URL : self::SF_LANGUAGE_PACK_URL;
         $url = str_replace(
@@ -1697,7 +1703,9 @@
      */
     public static function translationPackIsInCache(string $locale, string $type = self::PACK_TYPE_SYMFONY): bool
     {
-        return file_exists(self::getPathToCachedTranslationPack($locale, $type));
+        // EduBox: use runtime constant instead of class constant, because
+        // _PS_TRANSLATIONS_DIR_ may not be defined when this file is compiled.
+        return file_exists(_PS_TRANSLATIONS_DIR_ . $type . '-' . $locale . '.zip');
     }
 
     /**
@@ -1710,7 +1718,8 @@
      */
     private static function getPathToCachedTranslationPack(string $locale, string $type = self::PACK_TYPE_SYMFONY): string
     {
-        return self::TRANSLATION_PACK_CACHE_DIR . $type . '-' . $locale . '.zip';
+        // EduBox: use runtime constant instead of class constant.
+        return _PS_TRANSLATIONS_DIR_ . $type . '-' . $locale . '.zip';
     }
 
     /**