Problems with ECP (Exchange 2013)

Owa works perfectly, but when Im going to the /ECP I see only text and 500's. Its a DAG / Cluster, with two CA´s.Same error on both of them (Surfing to the local IP of CA1 and CA2), (DNS round robin).
In the eventviewer I see some MSExchange OAuth errors, (Event ID). and some ASP.NET errors, (Event ID 1309),
Anyone seen this error before and can guide me in the right direction