In order for the messages to be delivered as securely as possible in INBOX, different procedures must be followed depending on the provider.
1. Enable DMARC, DKIM and SPF in cPanel
These settings are recommended by the most important email service providers, such as Yahoo Mail or Gmail, so there is little chance that your messages will be filtered.
cPanel> Authentication - Enable DKIM and SPF for your account
cPanel> Zone Editor> (choose domain) Manage> + Add DMARC Record - enable DMARC registration in the DNS zone by clicking the Add record button.
2. Follow the recommendations of email service providers so that the delivery of messages is good.
Gmail https://support.google.com/mail/answer/81126?hl=en
Yahoo https://help.yahoo.com/kb/SLN24439.html
Outlook, Hotmail, Live https://postmaster.live.com/pm/policies.aspx
3. Recipients must use the 'Not Spam' option when messages are filtered incorrectly and / or add the sender's address to contacts.
