On 2024-02-29, Stefano Bagnara via mailop <mailop@mailop.org> wrote: > Today an italian mailvox provider started refusing our emails with this > message >> 550 5.1.0 <b+ourvariablereturnpath@e.#customerdomain> sender rejected: > domain does not have neither a valid MX or A record > > The "e.#customerdomain" is a CNAME record that points to app.mailvox.it and > app.mailvox.it has both A and MX records.
This situation is specifically permitted and covered in the DNS and Mail Routing RFCs, but may be less known than other configurations. As the problem went away, perhaps they introduced a bug when doing something else. _______________________________________________ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
