diff --git a/td/mtproto/TlsReaderByteFlow.cpp b/td/mtproto/TlsReaderByteFlow.cpp
index 8dafe044c..ad0abb1de 100644
--- a/td/mtproto/TlsReaderByteFlow.cpp
+++ b/td/mtproto/TlsReaderByteFlow.cpp
@@ -37,6 +37,7 @@ void TlsReaderByteFlow::loop() {
 
     output_.append(it.cut_head(len));
     *input_ = std::move(it);
+    on_output_updated();
   }
 }