Depending on the part where we see the failure and the type of failure, the first problem is to isolate where the problem is.
Let's look at an example. If a user reports that he is unable to reset his password using his Windows client, there are a number of errors that might have occurred, such as:
The client is missing the add-ins and extensions
The add-ins and extensions are not configured correctly
The user is not part of the required set
The MPR is misconfigured
The workflow activity is not working
FIM Service is missing some permissions in FIM Sync
The AD MA is not configured correctly
FIM Sync is unable to reset the password on the DC
The DCs are not replicating as expected
A long list, and I have probably still missed some. What I am trying to show is that we need quite a bit of information about the error, in order to narrow down where the problem lies.
I will not be able to give you a complete guide to all scenarios, I won't even try. Instead I will give you some common errors...