The most useful bit of information I've found so far is this from the kadmind log:
kadmind(Error): Failed setting up a RPC socket (for 0.0.0.0.749)
kadmind: Address already in use - Error setting up network
I read that this can be caused by the rpcbind service taking over the port
I've restarted the rpcbind service, but still cannot start the kadmin service.