diff --git a/pybtc/connector/connector.py b/pybtc/connector/connector.py
index 6eba26d..052f56c 100644
--- a/pybtc/connector/connector.py
+++ b/pybtc/connector/connector.py
@@ -363,7 +363,10 @@ class Connector:
 
             if self.utxo_data:
                 checkpoint = self.utxo.checkpoint
-                try: self.utxo.checkpoints.append(block["checkpoint"])
+                try:
+                    self.log.critical("append checkpoint " + str( block["checkpoint"]))
+
+                    self.utxo.checkpoints.append(block["checkpoint"])
                 except: pass
                 if len(self.utxo.cached) > self.utxo.size_limit and \
                    not self.utxo.save_process and \