Cannot read property 'length' of undefined

[jrtaaffe]

I get the following error when trying to run the app:

(node:8686) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'length' of undefined
at XmlEntities.exports.XmlEntities.XmlEntities.decode (/home/pi/sonos-swagger-api/node_modules/html-entities/lib/xml-entities.js:48:15)
at NotificationListener.notificationHandler (/home/pi/sonos-swagger-api/node_modules/sonos-discovery/lib/models/Player.js:262:42)
at NotificationListener.emit (events.js:203:15)
at NotificationListener.EventEmitter.emit (domain.js:448:20)
at parseLastChange.then (/home/pi/sonos-swagger-api/node_modules/sonos-discovery/lib/NotificationListener.js:125:17)
at process._tickCallback (internal/process/next_tick.js:68:7)