I have started a new thread both for convenience as there are a couple of other threads relating to this issue, and out of exasperation with the lack of progress in achieving a sustainable solution to the well-known problem related to sending ( or not ) of e-mails from various e-mail clients on different platforms.
There have been multiple instances highlighted on this forum of both this problem occuring regularly and the seemingly lack of any serious investigation of the problem by BT - we seem to get different messages from different 2nd line support people - if they ever ring back - and regularly get told it is not a BT server problem but is with the various clients - it is clear from this forum that is not the case.
My most recent e-mail failure started on 31 May and I thought it had been fixed yesterday - 'out of the blue' - as I was suddenly able to send e-mails from my BT Internet address on various clients e.g. Outlook and Mail on Windows and TypeApp and Gmail on Android.
However today e-mails have stopped being sent from all of the above clients.
To say this is frustrating is an understatement - If I still worked for BT I would be ashamed to put my name to such a flaky service - we are not back in the 90s when BT Internet started over dial-up! - e-mail is now core service and failures can seriously affect people. ( Apologies for pontificating but I am thoroughly p***ed off.
I will be raising another complaint whilst waiting, not holding my breath, for BT e-mail to ring me back.
Your issue does seem to be different to most of the other problems users report - in that you can't send emails.
Or do you also have the problem of receiving emails as well? In which case the issue is the same. Most don't actually report that sending can't be done, but I expect that's the case too.
Receiving mail is better but not consistent. The overall SMTP problem seems to be quite sporadic and even when 'fixed' has some interesting features e.g. got it working fine on Outlook on Windows 10 and TypeApp on Android phone but on MS Mail it seemed to take nearly a day to get through - I sent it yesterday afternoon and MS Mail said it had been sent ( i.e. not stuck in Outbox as per the usual problem ) but it didn't appear in any inboxes until today at nearly 15.00 - strange?
I am still waiting for BT to ring me back - the last agent on e-mail 2nd line support said I would, in future, only be supported by their manager!
Also waiting for BT Complaints procedure to kick in.