diff --git a/syncserver/__init__.py b/syncserver/__init__.py
index 563c5a4..cae3a0e 100644
--- a/syncserver/__init__.py
+++ b/syncserver/__init__.py
@@ -37,7 +37,7 @@ def includeme(config):
     settings = config.registry.settings
     public_url = settings.get("syncserver.public_url")
     if public_url is None:
-        raise RuntimeError("you much configure syncserver.public_url")
+        raise RuntimeError("you must configure syncserver.public_url")
     public_url = public_url.rstrip("/")
     settings["syncserver.public_url"] = public_url