Plugin_not_installed on ios devices after installing

I’m using cordova-plugin-webserver to start a local server.
I’ve run:

ionic cordova plugin add cordova-plugin-webserver
npm install @ionic-native/web-server

to install and included it in app.module.ts:

import {NetworkInterface} from '@ionic-native/network-interface/ngx';
  providers: [

When running on an iOS simulator or iOS real device, it reports error message as:

WARN: Native: tried calling WebServer.onRequest, but the WebServer plugin is not installed.
WARN: Install the WebServer plugin: 'ionic cordova plugin add cordova-plugin-webserver'
ERROR: plugin_not_installed

I tried to start server in the callback of this.platform.ready().then() or document.addEventListener('deviceready', () => {}) but it didn’t work.

I tried to remove iOS platform and re-add:

ionic cordova platform remove ios
ionic cordova platform add ios

It seems that someone else have the same problem on Android, which is reported in But the author didn’t respond for a long time.

Not sure if this is a problem with this plugin or a general problem with ionic. Could anyone suggest how I can deal with this problem? That would be a great help. Thanks in advance.

remove plugin and add it again then try

I’ve tried, but not worked.