smtp problem - sorry I've no idea what the thread prefix should be!

[ERob]

Sorry if this is in the wrong place, but a little help is needed.
I have a cpanel on reseller webhosting and access webmail through roundcube.
It's been working fine but now, when trying to send emails this message appears: SMTP error no support for delivery status notifications.
Any ideas why this has happened and what to do about it?

[SKaero]

You should contact your host and ask them about the error.