diff --git a/data/rbac-schema/src/main/java/net/corda/rbac/schema/RbacKeys.java b/data/rbac-schema/src/main/java/net/corda/rbac/schema/RbacKeys.java
index 1215b61a61..30bb1dadac 100644
--- a/data/rbac-schema/src/main/java/net/corda/rbac/schema/RbacKeys.java
+++ b/data/rbac-schema/src/main/java/net/corda/rbac/schema/RbacKeys.java
@@ -50,7 +50,7 @@ private RbacKeys() {
     /**
      * Flow start client request ID.
      */
-    public static final String CLIENT_REQ_REGEX = "[-._A-Za-z0-9]{1,250}";
+    public static final String CLIENT_REQ_REGEX = "[-._A-Za-z0-9]{1,242}";
 
     /**
      * FQN for a flow to be started.