Customize direct-delivery Postfix configuration

I setup the mail-receiver as it’s quick and simple… but when i go to check the handle mails it’s give me 404;

my site is subdomain like; forum.site.com

and in app mail-receiver i have this for the endpoint;

DISCOURSE_MAIL_ENDPOINT: ‘http://forum.site.com/admin/email/handle_mail

should i rebuild the discourse also ?