diff --git a/server/modules/monitor/mariadbmon/mysql_mon.cc b/server/modules/monitor/mariadbmon/mysql_mon.cc
index 9a7dc2e4d..cd1a8f79a 100644
--- a/server/modules/monitor/mariadbmon/mysql_mon.cc
+++ b/server/modules/monitor/mariadbmon/mysql_mon.cc
@@ -2373,8 +2373,9 @@ monitorMain(void *arg)
         }
 
         ss_dassert(handle->master == root_master);
-        ss_dassert((root_master->server->status & (SERVER_SLAVE | SERVER_MASTER))
-                   != (SERVER_SLAVE | SERVER_MASTER));
+        ss_dassert(!root_master ||
+                   ((root_master->server->status & (SERVER_SLAVE | SERVER_MASTER))
+                    != (SERVER_SLAVE | SERVER_MASTER)));
 
         /**
          * After updating the status of all servers, check if monitor events