diff --git a/addons/http_routing/models/ir_http.py b/addons/http_routing/models/ir_http.py
index 126fa64d5fb..6b2872f45b2 100644
--- a/addons/http_routing/models/ir_http.py
+++ b/addons/http_routing/models/ir_http.py
@@ -383,7 +383,7 @@ class IrHttp(models.AbstractModel):
             if nearest_lang:
                 lang = Lang._lang_get(nearest_lang)
             else:
-                nearest_ctx_lg = not is_a_bot and cls.get_nearest_lang(request.env.context['lang'])
+                nearest_ctx_lg = not is_a_bot and cls.get_nearest_lang(request.env.context.get('lang'))
                 nearest_ctx_lg = nearest_ctx_lg in lang_codes and nearest_ctx_lg
                 preferred_lang = Lang._lang_get(cook_lang or nearest_ctx_lg)
                 lang = preferred_lang or cls._get_default_lang()