NON-Katello - PXE boot fails for Ubuntu and CentOS VMs

Problem: PXE boot fails during the build process for both Ubuntu and CentOS at different stages.

Expected outcome: Successful PXE boot of either a CentOS or Ubuntu VM.

Foreman and Proxy versions: 3.7

Distribution and version: Foreman server is Ubuntu 20.04 LTS

Other relevant data:

I’m sure some of you have read my many posts about struggling with DHCP, then eventually TFTP… but with all that resolved, I have made it one step closer! PXE boot now starts!

For Ubuntu: I had to download and extract the Ubuntu ISO for the initrd and vmlinuz files to start the kickstart process as the ubuntu-mirror files were filled with 404 HTML documentation. The build process begins and after a few moments, starts spamming /dev/sr0 errors (like it is looking for a CD-rom? or USB maybe?) Eventually, it craps out and asks if I’d like to download the ISO from a web URL, but then complains the URLs I provide have bad addresses (assuming it can’t resolve things such as

Begin: trying netboot from ... Begin: Trying to download and mount ...

BusyBox v1.30.1 (Ubuntu 1:1.30.1-7ubuntu3) built-in shell (ash)
Enter 'help' for a list of built-in commands.

(initramfs) Connecting to ([2001:67c:1562::25:443)
wget: error getting response: Connection reset by peer
Unable to find a medium containing a life file system

For CentOS: The vmlinuz and initrd files built just fine using the CentOS mirror pointing to the CentOS repos… but then fails during dracut-initqueue stating:

dracut-initqueue: RTNETLINK answers: Invalid argument
dracut-initqueue: connect: Permission denied
dracut-initqueue: curl: (22) The requested URL returned error: 404 Not Found
dracut-initqueue: Warning: anaconda: failed to fetch kickstart from\&token=f52c10dc-9d48-41b0-8371-572f2b3919dc

Any advice? I feel like I’m FINALLY SO CLOSE! And this will be a huge weight off my shoulders if I could get Ubuntu (preferably) to load or CentOS or something.