diff --git a/llarp/router/i_outbound_session_maker.hpp b/llarp/router/i_outbound_session_maker.hpp
index 7bb5f3693..76ef6ddbd 100644
--- a/llarp/router/i_outbound_session_maker.hpp
+++ b/llarp/router/i_outbound_session_maker.hpp
@@ -39,7 +39,7 @@ namespace llarp
       case SessionResult::EstablishFail:
         return out << "establish failed";
     }
-    return out;
+    return out << "???";
   }
 
   using RouterCallback = std::function<void(const RouterID&, const SessionResult)>;
diff --git a/llarp/router/outbound_message_handler.cpp b/llarp/router/outbound_message_handler.cpp
index abbe54702..16e63b12d 100644
--- a/llarp/router/outbound_message_handler.cpp
+++ b/llarp/router/outbound_message_handler.cpp
@@ -154,8 +154,8 @@ namespace llarp
       case SessionResult::NoLink:
         return SendStatus::NoLink;
     }
-    // fall through case to appease compiler
-    return SendStatus::Congestion;
+    throw std::invalid_argument{
+        stringify("SessionResult ", result, " has no corrispoding SendStatus when transforming")};
   }
 
   void