1 files changed, 2 insertions, 2 deletions
diff --git a/synapse/handlers/oidc.py b/synapse/handlers/oidc.py
index deb3539751..8f71d975e9 100644
--- a/synapse/handlers/oidc.py
+++ b/synapse/handlers/oidc.py
@@ -544,9 +544,9 @@ class OidcProvider:
         """
         metadata = await self.load_metadata()
         token_endpoint = metadata.get("token_endpoint")
-        raw_headers = {
+        raw_headers: Dict[str, str] = {
             "Content-Type": "application/x-www-form-urlencoded",
-            "User-Agent": self._http_client.user_agent,
+            "User-Agent": self._http_client.user_agent.decode("ascii"),
             "Accept": "application/json",
         }