@Mahesh Thanks for the help. I managed to resolve it, thanks to your input.
I had to change the settings in Customize ▸ Theme Options▸ Homepage / Frontpage Options
A single category was selected and so posts only from that category were displaying on the homepage. I selected all categories and that fixed it.
P.S: It would be more convenient to have an option of selecting “all categories” rather than manually selecting all categories.
On another note, I could use some help with the thumbnail sizing on the homepage. The image gets cropped and appeared skewed. I did try regenerate thumbnails but that too didn’t help.
Thanks.