A common scenario that we see in support for the FIM Service Management Agent is one of two error messages:
We have been collecting this information, and documenting our findings. Please find below a series of different Microsoft TechNet Wiki articles that we have written.
Here is one more solution to add to the list of resolutions for Failed to retrieve schema errors when creating FIM MA.
After going through all of the resolutions I decided to review the authentication in IIS Administrator and saw that the pool was set to integrated, I changed it to classic restarted IIS and try to create the FIM MA again. It worked immediately. go figure.