diff --git a/synapse/app/pusher.py b/synapse/app/pusher.py
index f1de1e7ce9..3c3fa38053 100644
--- a/synapse/app/pusher.py
+++ b/synapse/app/pusher.py
@@ -311,7 +311,7 @@ class PusherServer(HomeServer):
                 poke_pushers(result)
             except:
                 logger.exception("Error replicating from %r", replication_url)
-                sleep(30)
+                yield sleep(30)
 
 
 def setup(config_options):
diff --git a/synapse/app/synchrotron.py b/synapse/app/synchrotron.py
index aa81e1c5da..7273055cc1 100644
--- a/synapse/app/synchrotron.py
+++ b/synapse/app/synchrotron.py
@@ -443,7 +443,7 @@ class SynchrotronServer(HomeServer):
                 notify(result)
             except:
                 logger.exception("Error replicating from %r", replication_url)
-                sleep(5)
+                yield sleep(5)
 
     def build_presence_handler(self):
         return SynchrotronPresence(self)