User accounts need project permission to have access to them. When inviting a new user that is not an Admin set access to projects you would like them to be involved in.
Step 1: Select User Management from your drop-down user menu.
Step 2: Click on the Projects button next to the users name whose project assess you would like to update.
Step 3: Now you will see a list of all projects in your portfolio. Tick all projects you would like to this user to have access to and click Save.
Tip: Admin and Owner accounts have access to all portfolio projects at all times. This is why the Projects button is grayed out and disabled. To limit an Admin account to specific projects, downgrade permission level to Producer, Crew or Client.