diff --git a/src/capport/api/lang.py b/src/capport/api/lang.py
index e3c1911..3ff3e99 100644
--- a/src/capport/api/lang.py
+++ b/src/capport/api/lang.py
@@ -60,7 +60,7 @@ def detect_language():
             return
         else:
             # reset language
-            s.pop('lang')
+            s.pop('lang', None)
     lang = s.get('lang')
     if lang:
         lang = lang.strip().lower()