Server 2008r2. After power failure we noticed that dns zone won't load on the server holding FSMO role. DNS error logs indicated Event IDs 4521, 4004 and 4015 which all pointed to error replicating AD. The AD errors on the other hand have Event ID errors 2108, 448, 447, 1084. This causes ad objects not replicate changes across all other DCs, etc. How do we fix this? Thanks.