diff --git a/src/sakia/core/graph/base_graph.py b/src/sakia/core/graph/base_graph.py
index 3a2cd9398b6081eb0d67066095de94dda71facc8..7adc5d2dc3c20f5b7560deca321ba352e1dac856 100644
--- a/src/sakia/core/graph/base_graph.py
+++ b/src/sakia/core/graph/base_graph.py
@@ -107,7 +107,7 @@ class BaseGraph(QObject):
                             QLocale.dateFormat(QLocale(), QLocale.ShortFormat)
                         ),
                         'cert_time': certifier['cert_time'],
-                        'confirmation_text': self.confirmation_text(certifier['cert_time'])
+                        'confirmation_text': self.confirmation_text(certifier['block_number'])
                     }
 
                     self.nx_graph.add_edge(certifier['identity'].pubkey, identity.pubkey, attr_dict=arc, weight=len(certifier_list))
@@ -145,7 +145,7 @@ class BaseGraph(QObject):
                             QLocale.dateFormat(QLocale(), QLocale.ShortFormat)
                         ),
                         'cert_time': certified['cert_time'],
-                        'confirmation_text': self.confirmation_text(certified['cert_time'])
+                        'confirmation_text': self.confirmation_text(certified['block_number'])
                     }
 
                     self.nx_graph.add_edge(identity.pubkey, certified['identity'].pubkey, attr_dict=arc,