SQL Server 2014 Reporting Services issues I have set up SSRS on MS SQL 2014 Dev Edition using the ReportServer built in account as the Service Account.  

My machine name is: POUYASAGER
My local login is pyous
I have given the ReportServer account full permissions to:   

C:\Program Files\Microsoft SQL Server\MSRS12.MSSQLSERVER\Reporting Services


I have checked that SecureConnectionLevel is set to 0 in the rsreportserver.config file.

I set up ReportServer as the virtual directory so that the Report Server Web Service URLs would be: http://POUYASAGER:80/ReportServer

When I click on the link in the Reporting Services Configuration Manager which is the same as above, I get:

The permissions granted to user 'POUYASAGER\pyous' are insufficient for performing this operation. (rsAccessDenied)

When I navigate to: http://127.0.0.1:80/ReportServer, an authentication pop-up asks for a username and password.

When I navigate to the reports manager using: http://pouyasager:80/Reports, I get:
Error
Unable to connect to the remote server  

How can I get SSRS working properly?

EDIT: I added "localhost" to the host headers and still got the same error.
EDIT: Using Chrome with Admin permissions, I navigate to http://localhost:80/ReportServer with the same results.
Adding the account you are logging in on your OS will allow for you to connect to SSRS. You are provided with a 403 error message directly related to an access denied. The type of access being denied here is at the database level, mainly for the Reportserver$ database. Your OS login is unable to personify NT SERVICE since it does not have a login on the server and guest account being probably disabled.

Additionally, verify the following:
'C:\WINDOWS\Microsoft.NET\Framework\V2.0.050727\Temporary ASP.NET Files'. (or where ever your .NET framework is installed on your machine)

Right click on the "Temporary ASP.NET Files" and select properties->secutity.

See if the "NETWORK SERVICE" is already part of the "User/Group" section. If not add it by typing "Network Service".
If it's already there then grant the write permissions.