If speech resources are erratically available to your applications-sometimes they're available, but sometimes they're not-there may be problems with port contention between applications.
Check the port ranges used by the MRCP feature and the other applications and utilities running on your system.
If there is a port conflict, edit the MRCP configuration file (/vs/sproxy/cfg/mrcp.cfg) to reset the RTPBasePort
setting to prevent ongoing conflict.