All mail to sfr.fr via relay.plus.net is bouncing - 550 domain has no delivery address

[#1]

Looks like something is borked on relay.plus.net with respect to the sfr.fr domain. Any time I try and e-mail anybody at sfr.fr via relay.plus.net I get a bounce:

<***@sfr.fr>: host relay.plus.net[212.159.8.107] said: 550 <***@sfr.fr> recipient rejected - domain has no delivery address (DNS MX or A record) (in reply to RCPT TO command)

Works absolutely fine if I route via gmail or another SMTP relay, but this behaviour is consistent if going via relay.plus.net! 

Doing manual DNS lookups for MX records on sfr.fr shows everything normal and as expected!

[#2]

Hi,

Issues similar to this have been seen before, due to a handful of causes, including but not limited to issues with the domain's nameservers (an external issue) and slow responses from DNS servers (an internal issue).

As you report, nslookup (using Plusnet's DNS servers) deliver MX details.  Is this a solid error?  Have you tried again to send the email?

Posting the email subject, date, time and message ID might assist Plusnet staff's investigations.

Superuser citation

This topic has been cited by one of the Superusers; the purpose of which is to provide a note for information which might help to focus continued discussion (but might not result in a staff response).

[#3]

Thanks for the reply Townman.

The problem persisted for over a week, but after posting this thread and tweeting plusnethelp, the problem has resolved as of today.