diff --git a/changelog.d/15746.bugfix b/changelog.d/15746.bugfix
new file mode 100644
index 000000000..8d3e22f2e
--- /dev/null
+++ b/changelog.d/15746.bugfix
@@ -0,0 +1 @@
+Fix regression where using TLS for replication did not work. Introduced in v1.85.0.
diff --git a/synapse/http/replicationagent.py b/synapse/http/replicationagent.py
index 800f21873..d6ba6f0e5 100644
--- a/synapse/http/replicationagent.py
+++ b/synapse/http/replicationagent.py
@@ -76,7 +76,7 @@ class ReplicationEndpointFactory:
                 endpoint = wrapClientTLS(
                     # The 'port' argument below isn't actually used by the function
                     self.context_factory.creatorForNetloc(
-                        self.instance_map[worker_name].host,
+                        self.instance_map[worker_name].host.encode("utf-8"),
                         self.instance_map[worker_name].port,
                     ),
                     endpoint,