address feedback

Author: jaymode

x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/Security.java

@@ -1062,7 +1062,9 @@ public void accept(DiscoveryNode node, ClusterState state) {
                 License license = LicenseService.getLicense(state.metaData());
                 if (license != null &&
                     FIPS140LicenseBootstrapCheck.ALLOWED_LICENSE_OPERATION_MODES.contains(license.operationMode()) == false) {
-                    throw new IllegalStateException("License operation mode [" + license.operationMode() + "] is not valid for FIPS");
+                    throw new IllegalStateException("FIPS mode cannot be used with a [" + license.operationMode() +
+                        "] license. It is only allowed with a Platinum or Trial license.");
+
                 }
             }
         }

x-pack/plugin/security/src/test/java/org/elasticsearch/xpack/security/SecurityTests.java

@@ -308,7 +308,7 @@ public void testJoinValidatorForFIPSLicense() throws Exception {
         } else {
             IllegalStateException e = expectThrows(IllegalStateException.class,
                 () -> new Security.ValidateLicenseForFIPS(true).accept(node, state));
-            assertThat(e.getMessage(), containsString("is not valid for FIPS"));
+            assertThat(e.getMessage(), containsString("FIPS mode cannot be used"));
         }
     }