System.unauthorized access exception when using AX 4.0 Enterprise portal

The cause of these errors are due to the Business Connector Proxy and
Internet Information Server (IIS) Application Pool owners having
insufficient rights on the IIS Server.

Resolution

To Resolve the errors, you will need to:

1) Make sure the Business Connector Proxy user and the IIS Application
Pool owner for the Enterprise Portal website match.

2) Add the Business Connector Proxy and IIS Application Pool owner to
the following local Windows Groups on the IIS server:

Power Users
Performance Monitor Users group

3) Reset IIS (Click Start, Click Run, type: IIS Reset, and click 'ok'