1. Add your domains in SpamExperts, please refer to here
3. Set up SPF: add the following TXT record at your domain
v=spf1 a:spf.cleverspeed.com ip4:server ip address -all (replacing with your server IP address)
Note: If your domain has an existing TXT record, add "a:spf.cleverspeed.com ip4:server ip address" to your existing TXT record. For example, if your current TXT record is "v=spf1 xxxxxx -all", change it to "v=spf1 xxxxxx a:spf.cleverspeed.com ip4:server ip address -all"
If you are using ReadySpace nameserver, please refer to here for editing DNS records
4. Set up a smarthost for your SMTP server: mxcluster.cleverspeed.com: 587