First make sure the A and ptr records configured correctly for your domain, we could use MXTOOLBOX to check that.
Reverse DNS is something set at your ISP level, not on your Exchange server. If you have a static IP from your provider you should be able to contact them (or log into the ISP's portal) to change the reverse DNS.
Here is also an article introduces about Managing SPF and reverse DNS in Exchange Server (Part 3)
And a related thread here for your reference as well: unable to send emails to hotmail/outlook or live email address
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