diff --git a/patroni/validator.py b/patroni/validator.py
index d0e1fa01..f83bcf0d 100644
--- a/patroni/validator.py
+++ b/patroni/validator.py
@@ -370,7 +370,7 @@ schema = Schema({
   "postgresql": {
     "listen": validate_host_port_listen_multiple_hosts,
     "connect_address": validate_connect_address,
-    "proxy_address": validate_connect_address,
+    Optional("proxy_address"): validate_connect_address,
     "authentication": {
       "replication": userattributes,
       "superuser": userattributes,