diff --git a/panel/panel-api.py b/panel/panel-api.py
index feb77b0..3200b83 100644
--- a/panel/panel-api.py
+++ b/panel/panel-api.py
@@ -554,9 +554,10 @@ class Handler(BaseHTTPRequestHandler):
                 return
 
             app, err = read_app_info(name)
-            if err is not None:
+            if err is not None or app is None:
                 run_panelctl(["remove", name])
-                self._json(500, {"ok": False, "error": f"failed to read app state: {err.get('error', 'unknown error')}"})
+                err_msg = (err or {}).get("error", "unknown error") if err else "app state unavailable"
+                self._json(500, {"ok": False, "error": f"failed to read app state: {err_msg}"})
                 return
 
             if source_type == "raw":