You're missing pretty much everything in terms of information that could help us help you.
Which exact version? Which host OS? Which browser?
What "page" should they reach? The Home page? Or a specific dashboard?
User is in an application role. Application role has permission to subject area.
After having read and covered the points Christian asked for, you maybe want to review how security in OBIEE works because "has permission to subject area" is not even 1% of the possible permissions OBIEE has. There is a lot more than that required to see something in OBIEE.
Obiee 18.104.22.168.0 on windows 10/sql server 12 and active directory for username/passwords.
Three subject areas were created in BI Administration using Admin tool.
I created 3 application roles in em. Members were assigned to one of these roles. These 3 application roles are also members of BI Authors role.
In Admin tool I gave permission to each subject area using application role.
I can see the subject areas and create reports in Answers. But a new user cannot see the home page when she logs on to answers - although she has the application role for the specific subject area.
After logon she sees "You do not have permission to access this page".
Windows 10 is a desktop operating system and is NOT supported at all for running OBI.
"to access this page" means *PAGE* and not Subject Area.
Access rights to SAs mean nothing at all if yout access rights are not correct. As Gianni suggested yoy may want to first understand the security concepts.
Access to Home Page, Access to Answers, Access to...xyz. look at the permissions.
And: you do not create "reports" in Answers. You create "analyses". A "report" is a BI Publisher obkect and a completely different technology.