diff --git a/s3tests.conf.SAMPLE b/s3tests.conf.SAMPLE
index c0c5fd9..61c13df 100644
--- a/s3tests.conf.SAMPLE
+++ b/s3tests.conf.SAMPLE
@@ -104,6 +104,6 @@ azp=<obtained after introspecting token>
 
 user_token=<access token for a user, with attribute Department=[Engineering, Marketing>]
 
-thumbprint=<obtained from x509 certificate>
+thumbprint=<obtained from x509 certificate and is longer than 40 characters>
 
 KC_REALM=<name of the realm>