You need clean smtps, don't count too much the mailer. If your smtp is from @domain.com and you send emails from @anotherdomain.com what you expect these days to deliver the email into inbox? Also the biggest webmails have filters, if you send from same ip too many emails they block your ip for 1h/10h/24h depends... the email content try to make it unique because if is the same the webmail will mark your ip as a spammer, there are many another things to hit the inbox, not the mailer.
Hi jsmith , i am agree with you about clean smtp , filters , etc etc .. but the point you said about from @domain.com and @anotherdomain.com its really not true .. this really not important to use same domain you configured in smtp although its really important to Aunthentication @anotherdomain via @domain.com .. what exactly you need to get good inbox rate is
1- Clean ips doesnt matter if virgin you can build reputation although its take 30 to 45 days
2- Clean list with low bounce rate
3- Spam keyword free campaign
4- Proper Authentication dkim , domain key , spf ,sender id
5- proper bounce processing
6- always handle unsubscribers properly
7- Secured server
8- sending with proper ISP rules according to their limit per ip .. give them respect they will return it to you
9 - focus on your email subject should not be spammy
10- never send same campaign to same users
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Mailing is easy if you know how to proceed
Ping me if you guys still looking for any solution
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