Three things decide what a person can reach, checked in this order.
1. Their role
Roles carry different access, and the difference is deliberate: financial detail, customer records and administrative settings are each held to the role that needs them.
Team access shows the role each person holds and what it includes. Changing a role takes effect the next time they load the page.
2. Which workspace they are in
Someone invited to one workspace does not see another. Where a business has more than one, a person can be a member of one and absent from the other entirely — see workspace.
3. Whether the area depends on a connection
Some areas populate from a connected system. Where the connection is not in place, the area is empty for everyone regardless of role — see I cannot see something I expect to.
They never received the invitation
Invitations go to a specific address and expire. Where one was not acted on, reissuing it is the route — see inviting a team member.
They can see it and cannot change it
Several roles are read-only by design in areas they can view. This is a distinct state from having no access, and it is what the role was set to.
Deciding what someone should have
The general principle is the access their work requires. Roles and what each carries are set out in roles and permissions.