smtp settings problem

When I try to send an email I get an error thing saying the server refused the recipients email (or something like that).
The diagnostic bit for accounts says ‘send failed’ and if I click on ‘fix’ it manages to send a test message but I still can’t reply to emails using these settings.
When emclient claims it has fixed the problem it has changed the host and port from what the email provider stipulates.
Email provider settings : Server:, Port: 587, STARTTLS
emclient changes them to :, Port: 25

The email provider settings work OK in thunderbird.

I have been reading lots of posts like this on the forum so not holding out much hope for a fix,  I was liking the look of emclient up to this point but might have to abandon it.

You can try the following settings:

Port: 587
Security policy: Force usage of SSL/TLS

See if that works.

Thanks for the suggestion but emclient still says smtp failed

Think it might be fixed, have been trying other options and ‘force use of SSL/TLS’ appears to be working. Have sent test message OK.