I have recently setup SPF record for one of the clients and now it is causing few issues while sending emails to certain domains. It comes up with this error message:
There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.
<[Our Domain] #5.5.0 smtp;550 SPF: [Server IP] is not allowed to send mail from [Our Domain]>
This network has SBS2003 and as exchange resides on SBS, that is the only IP address which is allowed to send emails out. And even in the error message, it is the same IP address listed that should have allowed the mail to send. This issue is only with few selected domains wheras the emails can be sent to other domains. Can this be an issue with the recepient's server (SPF check rule)? What is causing this issue?