diff --git a/doc/config/yaml.yml b/doc/config/yaml.yml
index 1035ec99..299a1e6f 100644
--- a/doc/config/yaml.yml
+++ b/doc/config/yaml.yml
@@ -102,7 +102,7 @@ smtp_server:
   # The default port the SMTP server should listen on unless overriden by the PORT environment variable
   default_port: 25
   # The default bind address the SMTP server should listen on unless overriden by the BIND_ADDRESS environment variable
-  default_bind_address: ::
+  default_bind_address: "::"
   # The default port for the SMTP server health server to listen on
   default_health_server_port: 9091
   # The default bind address for the SMTP server health server to listen on