diff --git a/explorer.py b/explorer.py
index c68666f..a20f488 100644
--- a/explorer.py
+++ b/explorer.py
@@ -2096,8 +2096,18 @@ def choose_trajectory_title(axis_def: dict, axis: str, threshold: float = 0.65)
     else:
         try:
             st.plotly_chart(fig, use_container_width=True)
-        except Exception:
-            pass
+        except Exception as e:
+            st.error(f"Trajectories rendering failed: {e}")
+            # Always show diagnostics when rendering fails, regardless of trace_count
+            if get_debug_trajectories_enabled():
+                try:
+                    st.json(_last_trajectories_diagnostics)
+                except Exception:
+                    st.text_area(
+                        "Trajectories diagnostics (JSON failed)",
+                        json.dumps(_last_trajectories_diagnostics, default=str),
+                        height=240,
+                    )
 
 
 # ---------------------------------------------------------------------------