On a Forefront UAG array deployment for some reason when for an array member I disjoin and rejoin it to the array I got the following error after the login page of the portal.
After some research I notice something weird on the IIS Application Pools node. For obscure reason the Pools used by Forefront UAG switched to .Net 4.
When I switched back to .Net Framework 2.0 the following Application Pools all work fine again:
- Classic .NET AppPool