GitLab Fails to Clone Repository

Hi,

We host our own GitLab-EE instance in-house. We're currently on GitLab 12.1.1. We are using the latest version of Git on Windows.

As of yesterday, a lot of our users are unable to clone down or pull large repositories. This also seems to now be affecting even the less larger repositories when pulling. Users are getting the following error:

This error appears after cloning gets stuck at a particular percentage for a minute or two. Sometimes it works, sometimes it doesn't, it's a little intermittent. This only suddenly started happening yesterday.

Any ideas as to how we can diagnose this issue? Any logs that I can check for on the server? We're running CentOS 7.6. I'm reasonably new to Linux OS and self hosted GitLab instances, so go easy on me 😅

Many thanks!