diff --git a/llm_server/cluster/cluster_config.py b/llm_server/cluster/cluster_config.py
index 453fa33..891dfc1 100644
--- a/llm_server/cluster/cluster_config.py
+++ b/llm_server/cluster/cluster_config.py
@@ -1,5 +1,6 @@
 import hashlib
 import pickle
+import traceback
 
 from llm_server import opts
 from llm_server.cluster.redis_cycle import add_backend_cycler, redis_cycle
@@ -75,24 +76,28 @@ def get_backends():
         priority = b['priority']
         result[k] = {'status': status, 'priority': priority}
 
-    if not opts.prioritize_by_size:
-        online_backends = sorted(
-            ((url, info) for url, info in backends.items() if info['online']),
+    try:
+        if not opts.prioritize_by_size:
+            online_backends = sorted(
+                ((url, info) for url, info in backends.items() if info['online']),
+                key=lambda kv: -kv[1]['priority'],
+                reverse=True
+            )
+        else:
+            online_backends = sorted(
+                ((url, info) for url, info in backends.items() if info['online']),
+                key=lambda kv: estimate_model_size(kv[1]['model_config']),
+                reverse=True
+            )
+        offline_backends = sorted(
+            ((url, info) for url, info in backends.items() if not info['online']),
             key=lambda kv: -kv[1]['priority'],
             reverse=True
         )
-    else:
-        online_backends = sorted(
-            ((url, info) for url, info in backends.items() if info['online']),
-            key=lambda kv: estimate_model_size(kv[1]['model_config']),
-            reverse=True
-        )
-    offline_backends = sorted(
-        ((url, info) for url, info in backends.items() if not info['online']),
-        key=lambda kv: -kv[1]['priority'],
-        reverse=True
-    )
-    return [url for url, info in online_backends], [url for url, info in offline_backends]
+        return [url for url, info in online_backends], [url for url, info in offline_backends]
+    except KeyError:
+        traceback.print_exc()
+        print(backends)
 
 
 def get_a_cluster_backend(model=None):