Cloning a git URL without username / password, but with credential.helper

I have a hosted version of Gitlab via the Bitnami Google Cloud launcher.

I'm trying to create a project that points to a repo behind a corp network, using a url like this:

https://servername.corpnetwork.com/myrepo

Instead of using a username / password, which won't work for our network since a new, unique token must be generated on every request, I'm using git extensions and credential.helper to generate a username and password on the Compute Engine server. I've verified this credential works and I can successfully do this when ssh'd into the compute engine instance:

user@gitlab-1-vm:~$ git clone https://servername.corpnetwork.com/myrepo

However, when trying to do the import through the Gitlab UI, I get the following error:

Error importing repository https://servername.corpnetwork.com/myrepo into root/myrepo - Cloning into bare repository '[REPOS PATH]/root/myrepo.git'... fatal: could not read Username for 'https://servername.corpnetwork.com/': No such device or address

Is it possible the Gitlab UI isn't using the same .gitconfig file that's setup on the Compute Engine server?