Git lock error

[Giulia1]

We have a looker-hosted instance and noticed that Looker's Production Mode doesn't match the master branch of our Git repository.

We tried to sync Looker's production branch to the repository's master branch by using a deploy webhook but received this error:

"JGIT Checkout Branch failed: Cannot lock /looker_data/modelshare/models/<project>/.git/index. Ensure that no other process has an open file handle on the lock file /looker_data/modelshare/models/<project>/.git/index.lock, then you may delete the lock file and retry."

Any ideas of how can we solve this problem?