Menu
Reply
netweaver
  • 2
  • 0
  • 0
Joining in
772 Views
Message 1 of 7
Flag for a moderator

421 4.1.0 MXIN400 Cannot validate your Mailfrom Domain xxx.xxx in DNS, adjust or retry later

Hi,

I'm hoping someone can help me - I'm posting on behalf of NetWeaver, a small web hosting company in the UK.

We're currently having this same problem: https://community.virginmedia.com/t5/Forum-Archive/Problems-receiving-emails/m-p/4130664#M2317958

To save you reading through - basically when our users try to contact any Virgin Media address, the message is rejected as the receiving mail server cannot verify the DNS properly.  This has just started today.

421 4.1.0 MXIN400 Cannot validate your Mailfrom Domain xxx.xxx in DNS, adjust or retry later

Does anyone know how this was resolved in the end?  Or perhaps have a contact I can speak with?

We're also noticing that Virgin Media users that use Virgin Media DNS resolvers are not able to access our sites, but can if they switch to other DNS resolvers - so it seems there's some kind of problem connecting back to our DNS servers.

Any help would be greatly appreciated.
Thanks,
Phil 

Tags (2)
0 Kudos
Reply
japitts
  • 18.23K
  • 2.36K
  • 4.17K
Very Insightful Person
Very Insightful Person
740 Views
Message 2 of 7
Flag for a moderator

Re: 421 4.1.0 MXIN400 Cannot validate your Mailfrom Domain xxx.xxx in DNS, adjust or retry later

Hey Phil,

I can't help directly, but I'm also with Netweaver for my personal domain (I use IMAP & authenticated SMTP) and VM purely for my connection.

I've just tried a quick test from my NW-SMTP to a Blueyonder test-account (I understand BY & VM are the same back-end server) and all has behaved as expected.

@ravenstar68  - I know I helped you with testing/replicating a Netweaver forwarding issue a month or so back, happy to do the same here if it helps.

I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more

Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks

ravenstar68
  • 19.63K
  • 1.15K
  • 8.62K
Very Insightful Person
Very Insightful Person
730 Views
Message 3 of 7
Flag for a moderator

Re: 421 4.1.0 MXIN400 Cannot validate your Mailfrom Domain xxx.xxx in DNS, adjust or retry later

@japitts 

I don't think it was Netweaver IIRC

I do remember that for some reason the DNS servers linked to VM's Mail Exchangers weren't talking properly to a specific set of authoritative servers used by some clients of the nethost involved.

@netweaver - I'm not a VM employee but are you able to drop me a sample domain that's experiencing issues.

jappitts - If everything's working for you - can I also have the domain that you're using.  I want to compare the DNS servers in use.

Tim

I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more

Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks

japitts
  • 18.23K
  • 2.36K
  • 4.17K
Very Insightful Person
Very Insightful Person
721 Views
Message 4 of 7
Flag for a moderator

Re: 421 4.1.0 MXIN400 Cannot validate your Mailfrom Domain xxx.xxx in DNS, adjust or retry later

I think, on reflection (and looking through my sent items for the tests), you're right Tim - the previous issue was with Namesco, not Netweaver....

Which renders my previous comment of "it's working ok" as irrelevant!!

Apologies both. Although as point of note for Phil - Tim isn't VM staff as he mentioned, but we're both part of the VM-VIP programme which is endorsed by Virgin Media, and Tim is the resident email guru on these boards.

I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more

Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks

0 Kudos
Reply
ravenstar68
  • 19.63K
  • 1.15K
  • 8.62K
Very Insightful Person
Very Insightful Person
711 Views
Message 5 of 7
Flag for a moderator

Re: 421 4.1.0 MXIN400 Cannot validate your Mailfrom Domain xxx.xxx in DNS, adjust or retry later

@japitts 

I've just done a look through my previous PM's and managed to find the thread.  It was actually econet that had issues before.

https://community.virginmedia.com/t5/Forum-Archive/Problems-receiving-emails/m-p/4130664#M2317958

I remember that econet support made the unprecedented offer of setting up an account so I could try and replicate the issue with a domain that I know was good.

Tim

Edit - PS we all make mistakes, don't beat yourself up about it.

I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more

Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks

0 Kudos
Reply
netweaver
  • 2
  • 0
  • 0
Joining in
689 Views
Message 6 of 7
Flag for a moderator

Re: 421 4.1.0 MXIN400 Cannot validate your Mailfrom Domain xxx.xxx in DNS, adjust or retry later

Hi @  & @  

Thank you so much for your replies.  

This morning the emails started flowing again as normal, almost exactly 48 hours after the first problem.  This leads me to believe it could have been a stale DNS cache in the VM resolvers, of our DNS server names which had an error - as they have a 48 hours TTL on them.

I'll keep a close eye on it over the next few days and if I see anything else, would it be acceptable to get back in touch with you?

Thanks
Phil 

0 Kudos
Reply
ravenstar68
  • 19.63K
  • 1.15K
  • 8.62K
Very Insightful Person
Very Insightful Person
683 Views
Message 7 of 7
Flag for a moderator

Re: 421 4.1.0 MXIN400 Cannot validate your Mailfrom Domain xxx.xxx in DNS, adjust or retry later

Definitely

Have you been changing your authoritative servers by any chance?

Tim

I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more

Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks

0 Kudos
Reply