diff --git a/src/CallHandler.js b/src/CallHandler.js
index 8dfd283e60..40a8d426f8 100644
--- a/src/CallHandler.js
+++ b/src/CallHandler.js
@@ -427,7 +427,8 @@ async function _startCallApp(roomId, type) {
         // URL, but this will at least allow the integration manager to not be hardcoded.
         widgetUrl = SdkConfig.get().integrations_jitsi_widget_url + '?' + queryString;
     } else {
-        widgetUrl = SdkConfig.get().integrations_rest_url + '/widgets/jitsi.html?' + queryString;
+        const apiUrl = IntegrationManagers.sharedInstance().getPrimaryManager().apiUrl;
+        widgetUrl = apiUrl + '/widgets/jitsi.html?' + queryString;
     }
 
     const widgetData = { widgetSessionId };
diff --git a/src/ScalarMessaging.js b/src/ScalarMessaging.js
index 8b87650929..5d3b3ae506 100644
--- a/src/ScalarMessaging.js
+++ b/src/ScalarMessaging.js
@@ -239,6 +239,7 @@ import dis from './dispatcher';
 import WidgetUtils from './utils/WidgetUtils';
 import RoomViewStore from './stores/RoomViewStore';
 import { _t } from './languageHandler';
+import {IntegrationManagers} from "./integrations/IntegrationManagers";
 
 function sendResponse(event, res) {
     const data = JSON.parse(JSON.stringify(event.data));
@@ -548,7 +549,8 @@ const onMessage = function(event) {
     // (See https://developer.mozilla.org/en-US/docs/Web/API/Window/postMessage)
     let configUrl;
     try {
-        configUrl = new URL(SdkConfig.get().integrations_ui_url);
+        // TODO: Support multiple integration managers
+        configUrl = new URL(IntegrationManagers.sharedInstance().getPrimaryManager().uiUrl);
     } catch (e) {
         // No integrations UI URL, ignore silently.
         return;
diff --git a/src/utils/WidgetUtils.js b/src/utils/WidgetUtils.js
index 41a241c905..5e127e48d5 100644
--- a/src/utils/WidgetUtils.js
+++ b/src/utils/WidgetUtils.js
@@ -27,6 +27,7 @@ import WidgetEchoStore from '../stores/WidgetEchoStore';
 const WIDGET_WAIT_TIME = 20000;
 import SettingsStore from "../settings/SettingsStore";
 import ActiveWidgetStore from "../stores/ActiveWidgetStore";
+import {IntegrationManagers} from "../integrations/IntegrationManagers";
 
 /**
  * Encodes a URI according to a set of template variables. Variables will be
@@ -102,7 +103,8 @@ export default class WidgetUtils {
 
         let scalarUrls = SdkConfig.get().integrations_widgets_urls;
         if (!scalarUrls || scalarUrls.length === 0) {
-            scalarUrls = [SdkConfig.get().integrations_rest_url];
+            const defaultManager = IntegrationManagers.sharedInstance().getPrimaryManager();
+            if (defaultManager) scalarUrls = [defaultManager.apiUrl];
         }
 
         for (let i = 0; i < scalarUrls.length; i++) {