Cannot sent email from onetel via TalkTalk App or Thunderbird

[CherryPicker9999]

I am a TalkTalk Fibre customer.

When I try and send a onetel.com  email via the app (https://apps.talktalk.co.uk/appsuite/), I receive the error message:

An error occurred inside the server which prevented it from fulfilling the request.

I am also using Thunderbird and have an email account from onetel.com.

Suddenly, if I try and send emails from the onetel address  I am getting an error message:

Sending of the message failed.
An error occurred while sending mail. The mail server responded:   Reject for policy reason. Please check the message and try again.

If I send an email via another address, such as gmail the email is delivered. Hence, it seems a talktalk issue.  I use:

smtp.talktalk.net

Port 587
STARTTLS
Normal password

I cannot sent emails from an onetel email address to any gmail addresses. I can sent to the same onetel email address.

Why are onetel emails being blocked?

[CherryPicker9999]

Whilst this is being resolved, the DMARC settings on onetel.com have settings that prevent users from sending emails via  another SMTP service provider.

If one cannot send emails out (despite being a TalkTalk customer) they have problems if the address is associated with certain companies which will only respond to the registered email address they have on file. Such a hassle to go and change the email address at all institutions.  I have used onetel for over 20-years. I guess one has to migrate if this issue persists.

I suspect the policy restriction means that the onetel email account has not been registered as being associated with a TalkTalk internet account.

Does one need to register (or re-register) from: https://service.talktalk.co.uk/register-account/identify?

[Ady-TalkTalk]

Hi CherryPicker9999, I've been told "we were unable to replicate the issue either way using the test accounts we have access to.  There is nothing on TT downdector reporting email issues either which is usually a good standpoint to confirm we have issues"

I'll now raise your issue as an individual fault. 

Ady

[CherryPicker9999]

I ran anti virus and changed password via forgot password as I cannot see an option in the app.

Emails still are not sent.

[Ady-TalkTalk]

Hi CherryPicker9999, please send me a personal message with the affected email address and I'll get this checked. 

Ady