Recently I worked with the Managed Client Object Model of Project Server 2013. Although being Farm Administrator, Site Collection Administrator (Site Owner) of every site collections and member of the Administrators group in Project Server, I received an Access Denied error (UnauthorizedAccessException) when executing even the simplest queries like this one:
The error message was:
Access denied. You do not have permission to perform this action or access this resource.
Error code: –2147024891
No entries corresponding the error or the correlation ID in the response was found in the ULS logs.
The real problem was the pwaUrl parameter in the ProjectContext constructor: by mistake I used the URL of the root site (like http://projectserver) instead of the URL of the PWA site (http://projectserver/PWA).