Hi @angad,
uhm sorry about that, it’s quite bizarre 
Could you try building v6.22/06 instead (git checkout v6-22-06) and see if that helps?
Also note that unless you have specific needs you don’t have to compile ROOT from sources: you can choose between a few simpler and quicker installation methods (e.g. you can install ROOT via conda), and recently a snap package was also made available for Ubuntu.
@Axel or @oshadura might have a hunch about what’s wrong with the TBB and VDT downloads.
Cheers,
Enrico