We have some '.co' domains for our company and recently decided to host email ourselves on one of the domains. We tried sending email to all major email providers like outlook, yahoo.. etc. All of these emails go to regular inbox, except in the case of GMail.
This is not bulk email but rather individual emails sent from our staff to customers or each other.
Some important things we made sure work 1000%:
1. Our VPS IP is not in blacklist ...and it shows good reputation by every blacklist company we could find.
2. SPF has been set up correctly
3. DKIM has been set up correctly
4. This domain was verified through postmaster.google.com
5. This domain was verified through google.com/webmaster
6 these settings have been in place for over a month, and we have been trying to get thus work for over half a year to no avail.
7.Bulk guidelines are met despite the fact that we don't send bulk emails.
Our clients are not receiving their invoices or communication from us unless they look in spam folder, this is insane since 80% of our clients use gmail
can someone advice what will be best possible solution.