TF282808: An error occurred when sending status update to Project Server during synchronization.

I am integrating tfs 2012 with project server 2013 using claims based authentication mode.

When I create a task in tfs and submit it to project server, my task is seen in project server but its  Last submit staus under the project server tab remains failure.

Also i get the following error:

TF282808: An error occurred when sending status update to Project Server during synchronization. Returned error code: "GeneralUnhandledException". Contact your Project Server administrator and report the error code.

Any help in this regard will be very helpful.

Thanks