[Mailer] Update mailer.rst

cadjou · javiereguiluz · commit 5d8a9e25130e · 2021-01-22T15:14:05.000+01:00
diff --git a/mailer.rst b/mailer.rst
@@ -65,6 +65,13 @@ over SMTP by configuring the DSN in your ``.env`` file (the ``user``,
             ]);
         };
 
+.. caution::
+
+    If the username, password or host contain any character considered special in a
+    URI (such as ``+``, ``@``, ``$``, ``#``, ``/``, ``:``, ``*``, ``!``), you must
+    encode them. See `RFC 3986`_ for the full list of reserved characters or use the
+    :phpfunction:`urlencode` function to encode them.
+
 .. caution::
 
     If you are migrating from Swiftmailer (and the Swiftmailer bundle), be
