550 error on occasion
FIXED- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page
- Plusnet Community
- :
- Forum
- :
- Help with my Plusnet services
- :
- :
- Re: 550 error on occasion
08-11-2017 12:27 AM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Hi
For a few years I've been happy sending mails from my Synology NAS, which relays via Plusnet. However in the past couple of weeks I've been getting sent email bounced back with the following error message (addresses changed!)
Reporting-MTA: dns; mydomain.co.uk
X-Postfix-Queue-ID: 48F9D49E
X-Postfix-Sender: rfc822; me@mydomain.co.uk
Arrival-Date: Tue, 7 Nov 2017 23:50:46 +0000 (GMT)
Final-Recipient: rfc822; the.recipient@yahoo.com
Original-Recipient: rfc822;the.recipient@yahoo.com
Action: failed
Status: 5.0.0
Remote-MTA: dns; relay.plus.net
Diagnostic-Code: smtp; 550 <me@mydomain.co.uk> sender rejected - invalid
domain (no MX or A record)
This doesn't always happens and if I resend the message it seems to work, though I have had reports of messages not being received.
I know we always claim that nothing has been changed but I'm pretty sure that it hasn't - NAS updates aside.
I've just done a test to/from my gmail account.
mydomain -> gmail - worked
gmail -> mydomain - worked
mydomain -> gmail - failed, resent - worked
gmail > mydomain - worked
mydomain -> gmail - worked
As the error text is related to A/MX records could the problem lie with my domain registrar?
Any ideas welcome.
Cheers
Andy
Fixed! Go to the fix.
Re: 550 error on occasion
09-11-2017 2:54 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Re: 550 error on occasion
18-11-2017 10:32 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Hi Adam
Pm'd a few days ago. Any progress on this. I note another user has reported the same problem:
https://community.plus.net/t5/Email/False-rejection-of-valid-sender-domain/td-p/1492200
Cheers
Andy
Re: 550 error on occasion
28-11-2017 1:16 AM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Apologies for replying to my own thread...
but this situation is still happening.
Just today - 27 Nov - I tried to send an email and twice got the same error - this is not an account I use much but the communications are important. I sent it a third time and that time no error message was generated, though having not heard back I've no confidence that all's well. I note that another poster is having the same issues.
Either this works or it doesn't, either my A/MX records are correct or they aren't.
I did send a PM but have heard nothing back.
Looking forward to an official reply.
Andy
Re: 550 error on occasion
28-11-2017 9:11 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Hi Andy,
Chuck a PM my way and I'll try to help, just need to know the domain in question.
The error is pretty cut and dry though. For one reason or another our relay server is failing to lookup the MX records for your domain.
Bob Pullen
Plusnet Product Team
If I've been helpful then please give thanks ⤵
Re: 550 error on occasion
28-11-2017 9:22 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Hi Bob
PM sent
Many thanks
Andy
Re: 550 error on occasion
28-11-2017 9:41 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
This doesn't look right to me.
An MX lookup on your domain is returning a CNAME record!?
~ $ dig [redacted].co.uk mx @212.159.6.10 ; <<>> DiG 9.9.5-9+deb8u13-Raspbian <<>> [redacted].co.uk mx @212.159.6.10 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 16544 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;[redacted].co.uk. IN MX ;; ANSWER SECTION: [redacted].co.uk. 3600 IN CNAME [redacted].diskstation.me. ;; AUTHORITY SECTION: diskstation.me. 300 IN SOA ddns-ns1.quickconnect.to. domain.synology.com. 10259881 3600 300 604800 3600
Whilst some servers might handle this, I'm fairly certain it's against RFC's.
As to why the issue is only intermittent when using our relays, I don't know
Bob Pullen
Plusnet Product Team
If I've been helpful then please give thanks ⤵
Re: 550 error on occasion
28-11-2017 9:48 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
To clarify how to address this, an MX record should be created in DNS to point to a subdomain. That subdomain should then be pointed to an IP address using an A record.
e.g:
plus.net. MX mx.avasin.plus.net. mx.avasin.plus.net. A 212.159.9.200
Bob Pullen
Plusnet Product Team
If I've been helpful then please give thanks ⤵
Re: 550 error on occasion
28-11-2017 9:55 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Hi Bob
Thanks for the prompt replies.
I'm a bit out of my technical comfort zone now!!! It would have been me who set up the original CNAME entries at 1&1. I wasn't running a mail server originally and the CNAME worked fine for the Synology DDNS service. When I added the mail server it just worked. I have to hang my head in shame with regard to not knowing about RFCs.
From your second reply I guess the only proper fix is to have a fixed IP address?
Cheers
Andy
28-11-2017 9:58 PM - edited 28-11-2017 10:00 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Try creating an MX record with 1&1 using priority 5 (doesn't really matter what priority you use to be fair) and point it to the DDNS address, i.e. the same destination you've used for the CNAME.
The MX record should take priority, and I'm hoping this will resolve your problem.
Edit: you may need to wait for DNS to propagate, so wait until tomorrow before drawing any conclusions.
Bob Pullen
Plusnet Product Team
If I've been helpful then please give thanks ⤵
Re: 550 error on occasion
28-11-2017 10:08 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Hi again
OK, that sounds like something I can handle. Odd that it started throwing up errors just recently.
I'll have a look at this tomorrow morning - it's too late now! I'll let you know.
Many thanks for your expert assistance.
Andy
Re: 550 error on occasion
28-11-2017 10:19 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Agree, odd that it's only just started being a problem, however I'm not party to what Synology might have been doing behind the scenes with their DDNS solution.
Let me know how you get on.
Bob Pullen
Plusnet Product Team
If I've been helpful then please give thanks ⤵
Re: 550 error on occasion
29-11-2017 11:26 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Hi Bob
I set up the MX record as you recommended and finally all seems well but with one caveat.
I had to change my email clients' SMTP and IMAP hosts to my DDNS name rather than my domain name otherwise the servers weren't found.
Again many thanks.
Andy
PS it's due to the level of support found on this forum that I stay with this ISP
Re: 550 error on occasion
30-11-2017 10:59 AM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
The server host name settings in your email client should be those where the servers reside. Unless you are running your own mail server it would be unusual for these to reflect your domain name.
For example on Plusnet the IMAP host is imap.plus.net and for SMTP it is relay.plus.net.
Re: 550 error on occasion
30-11-2017 11:20 AM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Hi Spraxyt
Thanks for your contributon.
However I am running my own mail server, on my Synology NAS. Previously I could locate the hosts via the domain name but now have to use the DDNS name. I did notice when setting up the correct MX record info that my CNAME on the www subdomain had become reset. Putting this back restored my personal website to normaility. I suspect that the CNAME on the domain itself has vanished too.
I don't mind as long as it works!
Cheers
Andy
- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page