Suggest you open an SR with SUpport
What errors do you get in the AdminServer logs?
There is no error in the weblogic Admin server related to the oam registration.
I have also raised an SR with Oracle Support laste Friday and the support still working on it.
You will need to change the log level to trace:32 so it gives you a detailed log of what it has done. From there someone might be able to determine what went wrong. The logging in the IAM products is horrendous, some minor things are shown as ERRORS whereas some errors won't be shown until you put it in trace mode.