Thank you for looking at my question,
We run MS Exchange 2003 as part of SBS 2003. Users have started having mails to individuals at one company bounced back with the following error message:
You do not have permission to send to this recipient. For assistance, contact your system administrator.
<ourdomain.com #4.7.1 smtp;450 4.7.1 <firstname.lastname@example.org>: Recipient address rejected: SPF-Result=ourdomain.com: 'SERVFAIL' error on DNS 'SPF' lookup of 'ourdomain.com'>
I don't even know where to start with this so any and all help would be appreciated greatly.