Fix backward compatibility with old clients

client/internal/peer/signaler.go

@@ -93,7 +93,7 @@ func (s *Signaler) signalOfferAnswer(offerAnswer OfferAnswer, remoteKey string,
 
 			s.deliveryCheckNotSupported.Store(true)
 			if err := s.signal.Send(msg); err != nil {
-				log.Errorf("failed to send msg to signal: %v", err)
+				log.Warnf("failed to send signal msg to remote peer: %v", err)
 			}
 			return ErrSignalNotSupportDeliveryCheck
 		default:

signal/server/signal.go

@@ -119,7 +119,10 @@ func (s *Server) Send(ctx context.Context, msg *proto.EncryptedMessage) (*proto.
 		return &proto.EncryptedMessage{}, nil
 	}
 
-	return s.dispatcher.SendMessage(ctx, msg, false)
+	if _, err := s.dispatcher.SendMessage(ctx, msg, false); err != nil {
+		log.Errorf("error sending message via dispatcher: %v", err)
+	}
+	return &proto.EncryptedMessage{}, nil
 }
 
 // SendWithDeliveryCheck forwards a message to the signal peer with error handling