Are you able to use System::getNumDrivers() and System::getDriverInfo() to see what devices are available?
It is possible that another software has “locked” onto the ASIO driver before the application that uses FMOD is initialized. It generally isn’t recommended to use ASIO as the FMOD application’s driver unless you are absolutely certain that no other application could be using the ASIO driver.
You can use a function in your application to have a fallback driver if one driver doesn’t work.