Update u_e-webmail-site.md

docs/u_e-webmail-site.md

@@ -1,3 +1,5 @@
+**Edit**: TODO: This guide only applies to non SNI enabled configurations. The certificate path needs to be adjusted if SNI is enabled. Something like `ssl_certificate,key /etc/ssl/mail/webmail.example.org/cert.pem,key.pem;` will do.
+
 To create a subdomain `webmail.example.org` and redirect it to SOGo, you need to create a **new** Nginx site. Take care of "CHANGE_TO_MAILCOW_HOSTNAME"!
 
 **nano data/conf/nginx/webmail.conf**