+1 but showing the output file that shows the lack of convergence would help. Also providing the coordinates will help people to do testing on their own in order to figure out how to solve your problem. — Nike Dattani 8 hours ago

Even if the output file is too long, it would help just to clarify what specifically isn't converging. Does the SCF fail or does an opt step or does are the forces just not getting smaller and it times out? — Tyberius ♦ 7 hours ago

I'm not familiar with Gaussian at all, but it doesn't look like you've given any lattice vectors or specified periodic boundary conditions. Is this correct? — Phil Hasnip 12 hours ago

So its the SCF that is failing and it looks like it is after quite some time. Usually, this would mean the optimization wound up at a bad structure for which the SCF was too difficult to converge. Was the energy throughout that SCF cycle significantly different from the energies in the previous optimization steps (search SCF Done throughout the file)? How close was the geometry to convergence (search Item, under which there should be a list of convergence criteria and how close they were). — Tyberius ♦ 7 hours ago

It seems like scf did come really close at two places one of which was (SCF Done: E(RCAM-B3LYP) = -23237.5922015 A.U. after 19 cycles Convg = 0.3136D-08 -V/T = 2.025) but under the Item column only RMS converged, and that too only once. — Parmeet Singh EP 066 6 hours ago

It probably would be easiest to include the whole output file. I'm guessing its too big to put in the post itself, but you can add it this Github repo or include a pastebin link. — Tyberius ♦ 6 hours ago

@Tyberius I uploded the log file which has all the information using google drive — Parmeet Singh EP 066 4 hours ago