diff --git a/server/src/main/kotlin/suwayomi/tachidesk/i18n/LocalizationHelper.kt b/server/src/main/kotlin/suwayomi/tachidesk/i18n/LocalizationHelper.kt
index 3a6acf5e..a51c3843 100644
--- a/server/src/main/kotlin/suwayomi/tachidesk/i18n/LocalizationHelper.kt
+++ b/server/src/main/kotlin/suwayomi/tachidesk/i18n/LocalizationHelper.kt
@@ -39,7 +39,7 @@ object LocalizationHelper {
         return if (headerLang == null || headerLang.isEmpty()) {
             Locale.getDefault()
         } else {
-            Locale.lookup(Locale.LanguageRange.parse(headerLang), supportedLocales)
+            Locale.lookup(Locale.LanguageRange.parse(headerLang), supportedLocales) ?: Locale.getDefault()
         }
     }
 }