How to restrict agent to only one project

Question

Situation:

We have an external supplier who need access as agent to a ITSM project, but only that.

Done so far:

Added user to an Azure AD group (which we use for access to all Atlassian products) and added the group to the SM project. Fine so far.

Followed some guides for how to restrict access, for instance https://support.atlassian.com/jira-cloud-administration/docs/manage-project-permissions/ ,

but when logged in as the external user, I can see all ITSM project in our environment, not just the project for me.

How can I solve this problem? Would it be better to invite the user as external directly to the project, instead of using "existing internal users" in the setup?

Per Hallenborg · Answer

And also, when I click Customers Permission, all I get is "Somethings gon wrong". I am Global admin, but on this project something is wrong. I also get ERROR: 1AQFRTA

Per Hallenborg · Answer

Thanks. So if I understand it , we need to set Restricted access to all projects in order to make them not viewable?  Since we have all our projects Open, then we can't restrict access.

Per Hallenborg · Answer

Thanks for your reply. Seems that we have all projects open, so that can be the issue.

How do you restrict a separated group and its restriction, if everything is open?