Ive whitelisted bakabt.me from my host for now, but as said, simply adding an rDNS record
should solve it for more hosts.
Contacting your ISP if their control panel doesnt allow for automatically setting it should resolve that problem.
It might not solve it entirely (for that ip reputation etc also plays into it, especially since your mail server IP is listed in the MIPSpace-poor list, but I found that list to be garbage, that blocks AWS ips and the likes, so I dont use it), but not setting an rDNS record is absolutely one of the biggest problems you will have with email deliverability.
I decided to find out a bit more for you. The problems with the register email are the following:
- no rDNS set (reason why the email failed my spam filter)
- SPF: HELO does not match SPF record (softfail)
- SPF: sender does not match SPF record (softfail)
- current SPF record is: "v=spf1 mx a ptr ~all" which should be changed to include your ip adresses you sent mail from.
- additionally, there is currently no DKIM set
Those are the major problems with the email.