Mautic sending email issue

hi every time i try to send email out using my roundcube

it comes out with this error in mautic

[2019-10-10 09:48:40] mautic.ERROR: [MAIL ERROR] Sending failed for one or more recipients Log data: ++ Starting Swift_Transport_EsmtpTransport << 220 box.example.com ESMTP Hi, I’m a Mail-in-a-Box (Ubuntu/Postfix; see https://mailinabox.email/) >> EHLO example.co.uk << 250-box.example.com 250-PIPELINING 250-SIZE 134217728 250-VRFY 250-ETRN 250-STARTTLS 250-ENHANCEDSTATUSCODES 250-8BITMIME 250-DSN 250 SMTPUTF8 >> STARTTLS << 220 2.0.0 Ready to start TLS >> EHLO example.co.uk << 250-box.example.com 250-PIPELINING 250-SIZE 134217728 250-VRFY 250-ETRN 250-AUTH PLAIN LOGIN 250-ENHANCEDSTATUSCODES 250-8BITMIME 250-DSN 250 SMTPUTF8 >> AUTH LOGIN << 334 VXNlcm5hbWU6 >> c2FsZXNAYW50aWJvZHltYXJrZXRpbmcuY29t << 334 UGFzc3dvcmQ6 >> THluY2gyMDAx << 235 2.7.0 Authentication successful ++ Swift_Transport_EsmtpTransport started >> MAIL FROM: << 250 2.1.0 Ok >> RCPT TO: << 553 5.7.1 : Sender address rejected: not owned by user sales@example.com >> RSET << 250 2.0.0 Ok [] []
[2019-10-10 09:48:40] mautic.ERROR: [MAIL ERROR] Sending failed for one or more recipients Log data: >> MAIL FROM: << 250 2.1.0 Ok >> RCPT TO: << 553 5.7.1 : Sender address rejected: not owned by user sales@example.com >> RSET << 250 2.0.0 Ok [] []

could someone advise?

You seemingly are using a different user account to send with than you are authenticating with.

i am putting the correct username password and server settings? it only seems to occur on mautic

So you are using the same email address in all places? The error that you have shared does not support that statement.

i have attempted to send emails out of marketing software before by using the same email settings and it has worked. only when i use mautic it doesnt?

Post some screen caps of your settings (in PM if you prefer).

And also (again in PM) the exact error messages unsanitized so that I can compare them with the settings.

The error message clearly says that you are somehow using two different email addresses.