I cannot share an existing project in Neoload 5.0.4, the share option is greyed out despite the test function working correctly with the repo name in, an incorrect repo name says it can't connect - so I know the permissions are ok.
If the option is greyed out it means that your current license does not have the collaboration module. Go to the License management panel and check your module of your current license.
One more thing. Is it only the "share" option that is greyed out?
If yes then you have already a shared project that's why you can't share it again.