I am running GitLab Community Edition. I created a one new project in Gitlab. When I try to clone via http it says: 
remote: Not found fatal: repository 'http://myhost/test/sample.git' not found
I am running GitLab Community Edition. I created a one new project in Gitlab. When I try to clone via http it says: 
remote: Not found fatal: repository 'http://myhost/test/sample.git' not found
try this instead:
or
most of the time there is a problem with authentication.
Is that url valid? It probably should have https rather than http.
Go to the web interface of your GitLab server and copy the HTTPS or SSH url from there.