fix internal fault injection test fail CIEC-3526
diff --git a/src/test-apps/happy/tests/standalone/wdmNext/test_weave_wdm_next_mutual_subscribe_faults.py b/src/test-apps/happy/tests/standalone/wdmNext/test_weave_wdm_next_mutual_subscribe_faults.py
index 1568b9e..e3e4af1 100755
--- a/src/test-apps/happy/tests/standalone/wdmNext/test_weave_wdm_next_mutual_subscribe_faults.py
+++ b/src/test-apps/happy/tests/standalone/wdmNext/test_weave_wdm_next_mutual_subscribe_faults.py
@@ -57,6 +57,7 @@
                               "Weave_WDMUpdateRequestSendErrorAsync",
                               "Weave_WDMUpdateRequestBadProfile",
                               "Weave_WDMUpdateResponseBusy",
+                              "Weave_WDMUpdateRequestDropMessage",
                               "Weave_WDMPathStoreFull"]
         not_required_server_faults = wdm_udpate_faults