Hi Nitesh,
I have checked my remotes, they are fine.
$ git remote -v
origin https://github.com/PoisonAlien/maftools.git (fetch)
origin https://github.com/PoisonAlien/maftools.git (push)
upstream git at git.bioconductor.org:packages/maftools.git (fetch)
upstream git at git.bioconductor.org:packages/maftools.git (push)
I had no issues earlier pushing to master/release branch (in earlier releases).
I also did a fresh pull on a new branch, I still have the same issue.
$ git branch devel
$ git checkout devel
Switched to branch 'devel'
$ git pull upstream master