1. The rDNS (reverse DNS) problem is because probably you are on a VPS and the rDNS/PTR record is not set.
If your VPS is on SolusVM, you need to go to Network tab in your SolusVM control panel and edit/save the rDNS record. Or you can ask the hosting provider to set the PTR record for you.
2. Only after that, you will have to setup the SPF and DKIM record from CWP -> Email -> DKIM Manager. Just select your domain, and check the "enable SPF", then "Add DKIM" and you're done.