To address the block on Port 25 and some implementations of sending mail not supporting modern standards, we can provide access to a service that is available to send mail out on port 25 through. This provided by SMX.
Domain administrators will want to update their records to accommodate some recipients enforcing the use of Sender Policy Framework (SPF).
TXT: "include:spf.securemx.biz -all"
To be added to the whitelist of this service, please contact us on 0800 12 13 14 or via. email.