GitLab Workflow: Failed to open file on web. No GitLab project.

OS: Ubuntu 18.04.3 LTS

VSCode: 1.40.1

Extension: fatihacet.gitlab-workflow@2.1.1

I tried configuring GitLab Workflow but can't make it work. I'm using a custom server and edited the project setting.json adding

"gitlab.instanceUrl": "https://mygitlabserver.url/"

The server is only available in internal ethernet and I am connected via VPN and able the access the URL in the browser.

I furthermore created an Access Token with the attributes

api, read_user

and added it to the exact same gitlab instance as configured in the settings.

The gitlab workflow tab does not show content under ISSUES ASSIGNED TO ME register but "There is no issue assigned to you." (and correspondingly in the other registers).

When invoking

GitLab: Show issues assigned to me

the following error pops up:

GitLab Workflow: Failed to open file on web. No GitLab project. Source: GitLab Workflow (Extension)

Usually I am accessing git through the command line with my SSH Key. Do I need to set this up somewhere in the extension as well?

Furthermore I do have eamodio.gitlens@10.2.0 installed and active and this extension works.