I would like to point CNAME records for www.example.com to sub.example2.com. The hosting for example2.com is a shared hosting (cPanel without Addon domain feature).
So, what I did was to add a subdomain in the cPanel: sub.example2.com
I then added a CNAME record for www (and without www) of example.com to sub.example2.com
After propagation, www.example.com shows the default server page of the hosting instead of showing the sub domain contents. If I access this subdomain directly, it works fine.
Can somebody help me with these, please? Thanks.
If I understood your intent correctly, you have to tell cPanel that you want to serve www.example.com, not the other thing. Either that, or create a third virtual host somewhere (anywhere) that would handle www.example.com by doing a HTTP redirect to sub.example2.com.
Note also that you can't have a CNAME record for example.com without www, because a domain record already has SOA and NS records, and CNAME can't be combined with anything else - it has to be an A record.