diff --git a/tempest/exceptions.py b/tempest/exceptions.py
index f534f30..67faad5 100644
--- a/tempest/exceptions.py
+++ b/tempest/exceptions.py
@@ -70,7 +70,7 @@
 # of get_network_from_name and preprov_creds to tempest.lib, and it should
 # be migrated along with them
 class InvalidTestResource(exceptions.TempestException):
-    message = "%(name) is not a valid %(type), or the name is ambiguous"
+    message = "%(name)s is not a valid %(type)s, or the name is ambiguous"
 
 
 class RFCViolation(exceptions.RestClientException):