smtp error when trying to send an email with attachments

fridaybliss wrote: »

Hello! I'm getting below error when I try to send an email with attachments (10.4MB) to one of your mortgage advisers who I'm been emailing. Is there an outage in your mailsystem?

This is the mail system at host [REDACTED]


I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                   The mail system

<[REDACTED]>: host 127.0.0.1[127.0.0.1] said: 550 service
    unavailable (in reply to end of DATA command)


Final-Recipient: rfc822; [REDACTED]
Original-Recipient: rfc822; [REDACTED]
Action: failed
Status: 5.0.0
Remote-MTA: dns; 127.0.0.1
Diagnostic-Code: smtp; 550 service unavailable

Hi fridaybliss,

Thanks for getting in touch with us on Boards.

Please check with your own email system for help with this error message as emails are being received. Please also try sending the attachments in separate emails if you have attached too many.

Thanks,
Sarah