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Email sending fails from a Virginmedia connection,but works from a mobile connection

Tuning in

I am unable to send an email from any of my Virgin emails addresses ( &, on my virgin cable broadband connection.

Thunderbird error console shows

mailnews.smtp: Command failed: 525 Authentication Denied (VM305); currentAction=_actionAUTHComplete SmtpClient.jsm:514:19

mailnews.smtp: Authentication failed: Authentication Denied (VM305)

But if I switch my laptop wifi connection over to my mobile hotspot, then the email sends okay.

The same happens from my mobile if I switch from my VM WiFi, onto mobile data.

I can receive fine on the accounts on all connections, so I know there are NO password/account locked type of issues.

It seems to be a trust issue between internal parts of Virginmedia own network!


Very Insightful Person
Very Insightful Person

The VM305 error indicates your network's public IP Address appears on Spamhaus's lists, to confirm this perform the following steps from the device that cannot send:

  1. browse to and note the Your IP address is value
  2. go to
  3. enter the Your IP address is value (from step 1) in the Search single IP, domain or hash field and select Lookup
  4. follow the advice offered

NB be aware that if the network is not your home Virgin Media broadband then the public IP Address for that network maybe shared between its users, for example when using a mobile network. In these cases you are unlikely to be responsible for the Spamhaus listing and therefore there is nothing you can do to resolve the issue — the workaround is to (a) use webmail to send emails; (b) connect via another network

I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more
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Morning nifty1a,

Thanks for posting and welcome to our community 🙂

Sorry to hear you're having some issues with sending mail, have you been able to take a look at the advise from 用心棒 ?


I did check, and yes my external VM IP address is blacklisted. I haven't been sending any spam emails, so I don't know quite this has happened.

So Virginmedia's email servers are blocking my Virginmedia IP address from sending emails, and you say there is nothing Virginmedia can do about it?

That is unacceptable, I am paying for an email service. The family are all unable to send email from their Virginmedia emails via Outlook, Thunderbird etc.

Messing around using webmail, or hotspotting mobile phones is not the solution. Virgin need to fix the issue. 

Thanks for coming back to us nifty1a, nobody has said that theres nothing that can be done to help you with this on this thread. Have you been advised that we cannot help with this via somewhere else? I would be happy to take a further look into this for you but first I would need to confirm a few details via private message, please look out for my message and we can get started.
Kind Regards,

Forum Team
Forum Team

Thanks for coming back to me nifty1a, I also haven't changed anything from this side as I hadn't gone in to your account yet. This may have been a known fault that was being worked by our network team and resolved yesterday evening. If you're happy that its working now, so am I and we dont need to carry on investigating if the issues have been resolved.

If you have any further issues, please get in touch and we will be able to assist further. 

Kind Regards,