Unable to send BT emails from Apple Mail app on MacBook Pro

[Suz77]

Have called both companies and both are defensive and in 'not our problem' mode. So am trying to fix myself. Have checked Server Settings. Think OK. Incoming Port 993.. Outgoing Port 587. BT recommends IMAP with SSL enabled. And selecting 'My server requires authentification.'  Only possible glitch I can see is that Outgoing mail server, in Apple's serving settings, appears to be 'offline'. Could this be the problem and how do I solve, please? A test of sending an email within BT's webmail interface works fine, so it probably is Apple's problem? 

[licquorice]

Try port 465 with SSL for Outgoing (SMTP) server, make sure authentication is 'Plain' (or whatever Apple's terminology equivalent is)

[Suz77]

Thanks. Will try that. Weirdly, this time, just a few mins after I'd posted my question, the mail in the Outbox got sent! But the problem usually returns next morning . . .

[gg30340]

Try using a different email app such as Bluemail.

See link for correct settings.

BT Email server settings | BT Help

[Suz77]

Thank you. Will try the new settings.

[Suz77]

Still no improvement on this front. Tried different port, and other suggestions, apart from using a different email app which I'm not keen to do. Mysteriously, on Sunday morning, after about 10 am and on Monday the same, my outbox was mysteriously sent, all by itself. But today we're back in blockage mode. Emails just sit there. Password and account not recognised despite changes of password, log outs and logins, detetion and reinstallation of mail app. All the above . . . SIGH.

[Suz77]

AH. I've just noticed there is no Outbox showing in the options in my BT webmail account. That won't help . . . Any ideas how I fix that, please?