diff --git a/docs/CONFIG.md b/docs/CONFIG.md
index 25d41b9..eb4f8f4 100644
--- a/docs/CONFIG.md
+++ b/docs/CONFIG.md
@@ -37,7 +37,7 @@ the following structure, and set `MH_OUTGOING_SMTP` or `-outgoing-smtp`.
     "server name": {
         "name": "server name",
         "host": "...",
-        "port": 587,
+        "port": "587",
         "email": "...",
         "username": "...",
         "password": "...",