Application Error

uaeu.jobNav.Industry.get(params,filter,sortBy,sortOrder)[class:JNV0510]: uaeu.general.dbtools.DBSchema.executeSelectQuery(query) : uaeu.general.dbtools.DBSchema.getConnection() : uaeu.general.dbtools.UAEUConnection.getConnection(dbSource,connectionMode) : uaeu.general.dbtools.UAEUConnection.getDriverConnection(dbSource) : Listener refused the connection with the following error: ORA-12528, TNS:listener: all appropriate instances are blocking new connections .