diff --git a/trytond/protocols/wrappers.py b/trytond/protocols/wrappers.py
index 10b8cfee51..86aed0d654 100644
--- a/trytond/protocols/wrappers.py
+++ b/trytond/protocols/wrappers.py
@@ -38,8 +38,11 @@ class Request(_Request):
             else:
                 url = self.url.decode(self.url_charset)
             auth = self.authorization
-            args.append("%s@%s" % (
-                    auth.get('userid', auth.username), self.remote_addr))
+            if auth:
+                args.append("%s@%s" % (
+                        auth.get('userid', auth.username), self.remote_addr))
+            else:
+                args.append(self.remote_addr)
             args.append("'%s'" % url)
             args.append("[%s]" % self.method)
             args.append("%s" % (self.rpc_method or ''))