Centos 7 server (Postfix) outgoing emails at Hotmail only goes to spam folder

Hello I have a forum and i was used a hosting company and Cloudflare in front and i was able to send out emails using the cpanel exim and Cloiudflare dns entries that the hosting company set for me with no issues. Then i move to another server (Centos 7 + Postfix) without a control panel and i use Cloudflare again. The issue is that only at Hotmail the emails are going to spam folder..... The new server uses Postfix to send out emails (don't need to receive emails at the server at all) when a user register or ask for forgotten password and i never send out spam... The new server ip is not blacklisted at any service like spamhaus and the related sites. I have all related dns entries spf, dkim, dmark e.t.c and all are valid.... Even when i view the source of an email at Hotmail i am getting for all PASSED! I am using Google's MX records as i am using a mail@[login to view URL] with no issues. I set also the reverse dns at the hosting provider panel for my server hostname (the issue maybe is here as i don't know if Microsoft needs to validate that and if it can do that behind Cloudflare). I found a related solution using a cname workaround but that one block all emails and it was worst. So i am looking for a fix for this but without changing the Postfix or installing a mail server or disabling Cloudflare and so on.... Also keep in mind that i can provide any info that you need but not full access to the server or Cloudflare. Also i need to know how it was fixed. Thank you