diff --git a/src/calibre/srv/utils.py b/src/calibre/srv/utils.py
index 5e984e7bbf..59070521fe 100644
--- a/src/calibre/srv/utils.py
+++ b/src/calibre/srv/utils.py
@@ -121,3 +121,4 @@ class Corked(object):
     def __exit__(self, *args):
         if self.sock is not None:
             self.sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_CORK, 0)
+            self.sock.send(b'')  # Ensure that uncorking occurs