Hi!
Is this in a real DMZ (real as opposed to a home router definition of a DMZ) where you have to grant permission on a per port basis?
DNS usually use port 53 UDP but switches to port 53 TCP when the replies gets too long (or for zone transfers but this doesn’t apply here).
The DNS queries could appear to work if only port 53 UDP is allowed but could fail when it has to switch to port 53 TCP…
If the problem is not that then I wonder if the “name lookup timed out” might not be the actual error but something more like this:
It’s a different problem but it probably implicates the same servers and maybe you are not getting the right error message… Is your IP “new”?
Good luck and have a nice day!
Nick