diff --git a/locales/en/app.json b/locales/en/app.json
index 5b7ce69d..1310c8d5 100644
--- a/locales/en/app.json
+++ b/locales/en/app.json
@@ -74,6 +74,7 @@
   },
   "disconnected_banner": "Connectivity to the server has been lost.",
   "error": {
+    "call_is_not_supported": "Call is not supported",
     "call_not_found": "Call not found",
     "call_not_found_description": "<0>That link doesn't appear to belong to any existing call. Check that you have the right link, or <1>create a new one</1>.</0>",
     "connection_lost": "Connection lost",
@@ -82,6 +83,7 @@
     "e2ee_unsupported_description": "Your web browser does not support encrypted calls. Supported browsers include Chrome, Safari, and Firefox 117+.",
     "generic": "Something went wrong",
     "generic_description": "Submitting debug logs will help us track down the problem.",
+    "matrix_rtc_focus_missing": "The server is not configured to work with \"{{brand}}\". Please contact your server admin (Error Code: {{ errorCode }}).",
     "insufficient_capacity": "Insufficient capacity",
     "insufficient_capacity_description": "The server has reached its maximum capacity and you cannot join the call at this time. Try again later, or contact your server admin if the problem persists.",
     "open_elsewhere": "Opened in another tab",
diff --git a/src/RichError.tsx b/src/RichError.tsx
index 2565bfe2..8099be9b 100644
--- a/src/RichError.tsx
+++ b/src/RichError.tsx
@@ -5,15 +5,17 @@ SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
 Please see LICENSE in the repository root for full details.
 */
 
-import { type FC, type ReactNode } from "react";
 import { Trans, useTranslation } from "react-i18next";
 import {
+  ErrorIcon,
   HostIcon,
+  OfflineIcon,
   PopOutIcon,
 } from "@vector-im/compound-design-tokens/assets/web/icons";
 
+import type { ComponentType, FC, ReactNode, SVGAttributes } from "react";
 import { ErrorView } from "./ErrorView";
-import { type ElementCallError, type ErrorCode } from "./utils/ec-errors.ts";
+import { type ElementCallError, ErrorCategory } from "./utils/ec-errors.ts";
 
 /**
  * An error consisting of a terse message to be logged to the console and a
@@ -68,22 +70,41 @@ export class InsufficientCapacityError extends RichError {
 }
 
 type ECErrorProps = {
-  errorCode: ErrorCode;
+  error: ElementCallError;
 };
 
-const GenericECError: FC<{ errorCode: ErrorCode }> = ({
-  errorCode,
+const GenericECError: FC<{ error: ElementCallError }> = ({
+  error,
 }: ECErrorProps) => {
   const { t } = useTranslation();
 
+  let title: string;
+  let icon: ComponentType<SVGAttributes<SVGElement>>;
+  switch (error.category) {
+    case ErrorCategory.CONFIGURATION_ISSUE:
+      title = t("error.call_is_not_supported");
+      icon = HostIcon;
+      break;
+    case ErrorCategory.NETWORK_CONNECTIVITY:
+      title = t("error.connection_lost");
+      icon = OfflineIcon;
+      break;
+    default:
+      title = t("error.generic");
+      icon = ErrorIcon;
+  }
   return (
-    <ErrorView Icon={HostIcon} title={t("error.generic")}>
+    <ErrorView Icon={icon} title={title}>
       <p>
-        <Trans
-          i18nKey="error.unexpected_ec_error"
-          components={[<b />, <code />]}
-          values={{ errorCode }}
-        />
+        {error.localisedMessage ? (
+          error.localisedMessage
+        ) : (
+          <Trans
+            i18nKey="error.unexpected_ec_error"
+            components={[<b />, <code />]}
+            values={{ errorCode: error.code }}
+          />
+        )}
       </p>
     </ErrorView>
   );
@@ -92,7 +113,7 @@ const GenericECError: FC<{ errorCode: ErrorCode }> = ({
 export class ElementCallRichError extends RichError {
   public ecError: ElementCallError;
   public constructor(ecError: ElementCallError) {
-    super(ecError.message, <GenericECError errorCode={ecError.code} />);
+    super(ecError.message, <GenericECError error={ecError} />);
     this.ecError = ecError;
   }
 }
diff --git a/src/rtcSessionHelpers.test.ts b/src/rtcSessionHelpers.test.ts
index 5ef9d6a0..ef924750 100644
--- a/src/rtcSessionHelpers.test.ts
+++ b/src/rtcSessionHelpers.test.ts
@@ -156,7 +156,7 @@ test("It fails with configuration error if no live kit url config is set in fall
   }) as unknown as MatrixRTCSession;
 
   await expect(enterRTCSession(mockedSession, false)).rejects.toThrowError(
-    expect.objectContaining({ code: ErrorCode.MISSING_LIVE_KIT_SERVICE_URL }),
+    expect.objectContaining({ code: ErrorCode.MISSING_MATRIX_RTC_FOCUS }),
   );
 });
 
diff --git a/src/rtcSessionHelpers.ts b/src/rtcSessionHelpers.ts
index 03ab24d8..974679b1 100644
--- a/src/rtcSessionHelpers.ts
+++ b/src/rtcSessionHelpers.ts
@@ -18,7 +18,7 @@ import { AutoDiscovery } from "matrix-js-sdk/src/autodiscovery";
 import { PosthogAnalytics } from "./analytics/PosthogAnalytics";
 import { Config } from "./config/Config";
 import { ElementWidgetActions, widget, type WidgetHelpers } from "./widget";
-import { ElementCallError, ErrorCode } from "./utils/ec-errors.ts";
+import { MatrixRTCFocusMissingError } from "./utils/ec-errors.ts";
 
 const FOCI_WK_KEY = "org.matrix.msc4143.rtc_foci";
 
@@ -81,11 +81,7 @@ async function makePreferredLivekitFoci(
   }
 
   if (preferredFoci.length === 0)
-    throw new ElementCallError(
-      `No livekit_service_url is configured so we could not create a focus.
-    Currently we skip computing a focus based on other users in the room.`,
-      ErrorCode.MISSING_LIVE_KIT_SERVICE_URL,
-    );
+    throw new MatrixRTCFocusMissingError(domain ?? "");
   return Promise.resolve(preferredFoci);
 
   // TODO: we want to do something like this:
diff --git a/src/utils/ec-errors.ts b/src/utils/ec-errors.ts
index 504f4f76..c41759f8 100644
--- a/src/utils/ec-errors.ts
+++ b/src/utils/ec-errors.ts
@@ -5,29 +5,68 @@ SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
 Please see LICENSE in the repository root for full details.
 */
 
+import { t } from "i18next";
+
 export enum ErrorCode {
   /**
    * Configuration problem due to no MatrixRTC backend/SFU is exposed via .well-known and no fallback configured.
    */
-  MISSING_LIVE_KIT_SERVICE_URL = "MISSING_LIVE_KIT_SERVICE_URL",
+  MISSING_MATRIX_RTC_FOCUS = "MISSING_MATRIX_RTC_FOCUS",
   CONNECTION_LOST_ERROR = "CONNECTION_LOST_ERROR",
   // UNKNOWN_ERROR = "UNKNOWN_ERROR",
 }
 
+export enum ErrorCategory {
+  /** Calling is not supported, server miss-configured (JWT service missing, no MSC support ...)*/
+  CONFIGURATION_ISSUE = "CONFIGURATION_ISSUE",
+  NETWORK_CONNECTIVITY = "NETWORK_CONNECTIVITY",
+  // SYSTEM_FAILURE / FEDERATION_FAILURE ..
+}
+
 /**
  * Structure for errors that occur when using ElementCall.
  */
 export class ElementCallError extends Error {
   public code: ErrorCode;
+  public category: ErrorCategory;
+  public localisedMessage?: string;
 
-  public constructor(message: string, code: ErrorCode) {
-    super(message);
+  public constructor(
+    name: string,
+    code: ErrorCode,
+    category: ErrorCategory,
+    localisedMessage?: string,
+  ) {
+    super();
+    this.localisedMessage = localisedMessage;
+    this.category = category;
     this.code = code;
   }
 }
 
+export class MatrixRTCFocusMissingError extends ElementCallError {
+  public domain: string;
+
+  public constructor(domain: string) {
+    super(
+      "MatrixRTCFocusMissingError",
+      ErrorCode.MISSING_MATRIX_RTC_FOCUS,
+      ErrorCategory.CONFIGURATION_ISSUE,
+      t("error.matrix_rtc_focus_missing", {
+        brand: domain,
+        errorCode: ErrorCode.MISSING_MATRIX_RTC_FOCUS,
+      }),
+    );
+    this.domain = domain;
+  }
+}
+
 export class ConnectionLostError extends ElementCallError {
   public constructor() {
-    super("Connection lost", ErrorCode.CONNECTION_LOST_ERROR);
+    super(
+      "Connection lost",
+      ErrorCode.CONNECTION_LOST_ERROR,
+      ErrorCategory.NETWORK_CONNECTIVITY,
+    );
   }
 }