-- Verifying Times compatible math font. ** Times compatible math font not found, forcing. ** No Times compatible math font package found. newtxmath is required. ! LaTeX Error: File `newtxmath.sty' not found.
It appears that others also encountered similar. The solution is simple. It is just to install additional fonts that are Times compatible. I am using Texlive on a Ubuntu system. On Ubuntu, perhaps, other Debian-based Linux system, you can install additional fonts for LaTeX as follows,
The error went away after I installed the package.
sudo apt-get install texlive-fonts-extra