Sent Email going to spam folder ?

i have a own Office based Dedicated HPE server .also installed Directadmin web panel with roundcube email. i have use GoDaddy Name Server. all email configuration like DKIM,MX RECORD ,TXT RECORDS done . my server ip is not blacklisted .all incoming email received in inbox folder but when i sent email to Gmail or other Domain email address going to spam folder, not inbox want solution.
have to work through any desk.