diff --git a/synapse/rest/well_known.py b/synapse/rest/well_known.py
index 41d868c6d..d2e500d56 100644
--- a/synapse/rest/well_known.py
+++ b/synapse/rest/well_known.py
@@ -59,7 +59,7 @@ class WellKnownResource(Resource):
         self._well_known_builder = WellKnownBuilder(hs)
 
     def render_GET(self, request):
-	set_cors_headers(request)
+        set_cors_headers(request)
         r = self._well_known_builder.get_well_known()
         if not r:
             request.setResponseCode(404)