diff --git a/backend/internal/http/handler/user_generation.go b/backend/internal/http/handler/user_generation.go
index 5be054d..8bf12ec 100644
--- a/backend/internal/http/handler/user_generation.go
+++ b/backend/internal/http/handler/user_generation.go
@@ -458,7 +458,7 @@ func (h *UserGenerationHandler) catalogEntries(c *gin.Context) ([]gin.H, error)
 			"type":                 "video",
 			"ratios":               []string{"2:3", "3:2", "1:1", "9:16", "16:9"},
 			"resolutions":          []string{"720p"},
-			"durations":            []string{"6s", "10s", "15s"},
+			"durations":            []string{"6s", "10s"},
 			"max_reference_images": 6,
 			"reference_mode":       "asset",
 			"description":          "Grok Imagine video (文/图生视频)",
diff --git a/backend/internal/provider/grok/video.go b/backend/internal/provider/grok/video.go
index 2dcbb0f..6fbc4ae 100644
--- a/backend/internal/provider/grok/video.go
+++ b/backend/internal/provider/grok/video.go
@@ -140,7 +140,14 @@ func (c *Client) GenerateVideo(ctx context.Context, token, prompt, aspectRatio,
 		if artifact != "" {
 			break
 		}
-		// No artifact: grok closed the stream early. Retry.
+		// A fatal stream error means grok definitively rejected this generation
+		// (content moderation, an unsupported parameter, etc.). Retrying — on this
+		// or any other account — fails identically and only burns the pool, so fail
+		// fast with a non-temporary error the pool won't fail over on.
+		if strings.Contains(body, "STREAM_ERROR_SEVERITY_FATAL") {
+			return nil, nil, fmt.Errorf("grok: video generation rejected by upstream (fatal stream error): %s", clip([]byte(body), 200))
+		}
+		// No artifact and no fatal error: grok closed the stream early. Retry.
 		lastErr = nil
 	}
 	if artifact == "" {