don't get it working

[SvenM74]

mieleathome.0	2023-04-06 17:01:24.292	error	this.NRefreshToken is not a function
mieleathome.0	2023-04-06 17:01:24.290	error	TypeError: this.NRefreshToken is not a function at Request._callback (/opt/iobroker/node_modules/iobroker.mieleathome/utils/mieleathome.js:229:22) at self.callback (/opt/iobroker/node_modules/request/request.js:185:22) at Request.emit (node:events:513:28) at Request. (/opt/iobroker/node_modules/request/request.js:1154:10) at Request.emit (node:events:513:28) at IncomingMessage. (/opt/iobroker/node_modules/request/request.js:1076:12) at Object.onceWrapper (node:events:627:28) at IncomingMessage.emit (node:events:525:35) at endReadableNT (node:internal/streams/readable:1359:12) at process.processTicksAndRejections (node:internal/process/task_queues:82:21)
mieleathome.0	2023-04-06 17:01:24.287	error	uncaught exception: this.NRefreshToken is not a function