Surface error for missing key or url.

app/i18n/en-US/streaming.json

@@ -90,6 +90,8 @@
   "Missing required oauth scope": "Missing required oauth scope",
   "Failed to fetch platform settings": "Failed to fetch platform settings",
   "Failed to update platform settings": "Failed to update platform settings",
+  "Stream key missing. Relogin or remerge to refresh it.": "Stream key missing. Relogin or remerge to refresh it.",
+  "Server url missing. Relogin or remerge to refresh it.": "Server url missing. Relogin or remerge to refresh it.",
   "The Multistream server is temporarily unavailable": "The Multistream server is temporarily unavailable",
   "Failed to configure the Multistream server": "Failed to configure the Multistream server",
   "disable Enhanced Broadcasting for Twitch and try again": "disable Enhanced Broadcasting for Twitch and try again",

app/services/streaming/stream-error.ts

@@ -36,6 +36,16 @@ export const errorTypes = {
       return $t('Failed to update platform settings');
     },
   },
+  STREAM_KEY_MISSING: {
+    get message() {
+      return $t('Stream key missing. Relogin or remerge to refresh it.');
+    },
+  },
+  STREAM_SERVER_MISSING: {
+    get message() {
+      return $t('Server url missing. Relogin or remerge to refresh it.');
+    },
+  },
   RESTREAM_DISABLED: {
     get message() {
       return $t('The Multistream server is temporarily unavailable');

app/services/streaming/streaming.ts

@@ -783,10 +783,16 @@ export class StreamingService
     } catch (e: unknown) {
       console.error('Error starting video transmission: ', e);
 
-      const failureType =
-        e && (e as any).message && (e as any).message.includes('encoder')
-          ? 'INVALID_ENCODER'
-          : 'UNKNOWN_ERROR';
+      // A blank stream key or server url fails here as a bare `UNKNOWN_ERROR`, which tells the
+      // user nothing. Name the missing field instead when that is what went wrong.
+      const missingSetting = this.getMissingStreamSetting();
+
+      let failureType: TStreamErrorType = 'UNKNOWN_ERROR';
+      if (e && (e as any).message && (e as any).message.includes('encoder')) {
+        failureType = 'INVALID_ENCODER';
+      } else if (missingSetting) {
+        failureType = missingSetting === 'key' ? 'STREAM_KEY_MISSING' : 'STREAM_SERVER_MISSING';
+      }
 
       const errorType = this.handleTypedStreamError(
         e,
@@ -4397,6 +4403,37 @@ export class StreamingService
   private streamErrorUserMessage = '';
   private streamErrorReportMessage = '';
 
+  /**
+   * Whether an output failed because its stream settings were incomplete
+   * @remark OBS signals returns a generic `InvalidStream`/`BadPath` error when the stream failed to
+   * start due to misconfigured settings. Check for a missing key or url to surface that specific error,
+   * which is more helpful for the user.
+   * @param context - The output context that failed, as reported on the signal
+   * @returns The missing field, or `null` when the settings are complete
+   */
+  private getMissingStreamSetting(context?: string): 'key' | 'server' | null {
+    // The enhanced broadcasting instance streams Twitch, so it uses Twitch's display
+    let display: TDisplayType = 'horizontal';
+    if (context === 'vertical') {
+      display = 'vertical';
+    } else if (context === 'enhancedBroadcasting') {
+      display = this.views.getPlatformDisplayType('twitch');
+    }
+
+    const settings =
+      display === 'vertical'
+        ? this.settingsService.views.values.StreamSecond
+        : this.settingsService.views.values.Stream;
+
+    if (!settings.key) return 'key';
+
+    // `rtmp_common` resolves the ingest from the service, so an empty server is only a problem
+    // for a custom ingest
+    if (!settings.server && settings.streamType !== 'rtmp_common') return 'server';
+
+    return null;
+  }
+
   private handleOBSOutputError(info: IOBSOutputSignalInfo, platform?: string) {
     console.log('OBS Output Error signal: ', info);
 
@@ -4429,7 +4466,20 @@ export class StreamingService
     let showNativeErrorMessage = false;
     let diagReportMessage = this.streamErrorUserMessage;
 
-    if (info.code === EOutputCode.BadPath) {
+    // Surface a more specific error for a missing stream key or server url
+    const missingSetting =
+      info.code === EOutputCode.InvalidStream || info.code === EOutputCode.BadPath
+        ? this.getMissingStreamSetting(info.service)
+        : null;
+
+    if (missingSetting) {
+      const messages = formatStreamErrorMessage(
+        missingSetting === 'key' ? 'STREAM_KEY_MISSING' : 'STREAM_SERVER_MISSING',
+      );
+
+      errorText = messages.user;
+      diagReportMessage = messages.report;
+    } else if (info.code === EOutputCode.BadPath) {
       errorText = $t(
         'Invalid Path or Connection URL.  Please check your settings to confirm that they are valid.',
       );