In Thunderbird go to the email account you are wanting to check then Tools > Account Settings > In the left hand column click on Outgoing Server (SMTP) and check what is listed and if need be change them .
If they are all correct as this is not a BT problem there is nothing further I can do to help so unless another forum member can assist you will need to seek assistance from either Thunderbird or Microsoft
@BStacey wrote:
The description names of both servers in Thunderbird needs to be the same as the incoming and outgoing server names.
Click on server settings and you'll see one lot of settings - these should be:
IMAP server name outlook.office365.com
IMAP port 993
IMAP encryption method TLS
Once done, go to the scroll function on the left hand side and scroll all the way down to Outgoing Server SMTP.
Click on edit server and use these settings:
SMTP server name smtp-mail.outlook.com
SMTP port 587
SMTP encryption method STARTTLS
All of which are in the link I posted in message 4.
@BStaceywrote:
I've not done anything differently except try to email again and it has now sent and been received.
However, I've received this message to say that it didn't send:
Sending of the message failed.
An error occurred while sending mail: Outgoing server (SMTP) error. The server responded: Timeout waiting for client input [LO4P123CA0147.GBRP123.PROD.OUTLOOK.COM].
I'm guessing I'll try Thunderbird but at least I have outgoing emails again. Thanks a million!
If you're still getting a sent message failure, make sure that there is nothing in the outbox that could still be failing.