I have just upgraded to 2.4.0. I got the following error when running Setup Wizard.
Domain that you have provided is not configured as rDNS for your server IP. [404]
I used the following to check and both lookup to my domain. My actual ip address is replaced with 0.0.0.0 below.
dig -x 0.0.0.0 +noall +answer
There was no error when I used the same domain in 2.3.9. Is there a bug?