Error: Cannot read properties of undefined (reading 'cometd') when trying to load CometD in LWC

Question

I want to subscribe to events in a community using the CometD library. Unfortunately when loading the script I get following error: "Error: Cannot read properties of undefined (reading 'cometd')"

This is my code:

import { LightningElement, api, wire, track } from 'lwc';
import { subscribe, unsubscribe, onError, setDebugFlag, isEmpEnabled } from 'lightning/empApi';
import triggerSomeEventBoy from '@salesforce/apex/AccountController.triggerSomeEventBoy';
import getAllActiveAccounts from '@salesforce/apex/AccountController.getAllActiveAccounts';
import getSessionId from '@salesforce/apex/AccountController.getSessionId';
import { loadScript } from "lightning/platformResourceLoader";
import cometdlwc from '@salesforce/resourceUrl/CometD';


export default class GerkesComponent extends LightningElement {
    libInitialized = false;
    @track sessionId;
    @track error;

    sessionId = "";
    @wire(getSessionId)
    wiredSessionId(result) {
        var error = result.error;
        var data = result.data;
        if(data) {
            console.log('sesssion id: ' + data);
            this.sessionId = data;
            this.error = undefined;
            loadScript(this, cometdlwc).then(() => {
                console.log('script loaded yippie!');
                this.initializecometd();
            }).catch((error) => {
                console.log('found error:');
               console.log(error);
            });
        } else if (error) {
            console.log(error);
            this.error = error;
            this.sessionId = undefined;
        }
    }
}

Does anyone know why this error occurs and how to solve it?