diff --git a/src/sakia/data/entities/certification.py b/src/sakia/data/entities/certification.py
index 1cd5959ba8d35fda2042b151c77a719a9aeaea55..0b915289ba03930f33e92908a626293d3cf927cf 100644
--- a/src/sakia/data/entities/certification.py
+++ b/src/sakia/data/entities/certification.py
@@ -10,4 +10,4 @@ class Certification:
     block = attr.ib(convert=int)
     timestamp = attr.ib(convert=int, cmp=False)
     signature = attr.ib(convert=str, cmp=False, hash=False)
-    written_on = attr.ib(convert=int, default=0, cmp=False, hash=False)
+    written_on = attr.ib(convert=int, default=-1, cmp=False, hash=False)
diff --git a/src/sakia/data/graphs/base_graph.py b/src/sakia/data/graphs/base_graph.py
index b7e5f83565d166de3ad18461794e18085f7b5700..5e9c303f4b6cf513e36fdae25f3b970dbc138e86 100644
--- a/src/sakia/data/graphs/base_graph.py
+++ b/src/sakia/data/graphs/base_graph.py
@@ -80,7 +80,10 @@ class BaseGraph(QObject):
         :rtype: str
         """
         try:
-            current_confirmations = min(max(self.blockchain_service.current_buid().number - block_number, 0), 6)
+            if block_number >= 0:
+                current_confirmations = min(max(self.blockchain_service.current_buid().number - block_number, 0), 6)
+            else:
+                current_confirmations = 0
 
             if MAX_CONFIRMATIONS > current_confirmations:
                 if self.app.parameters.expert_mode:
@@ -130,7 +133,7 @@ class BaseGraph(QObject):
                 QLocale.dateFormat(QLocale(), QLocale.ShortFormat)
             ),
             'cert_time': certification.timestamp,
-            'confirmation_text': self.confirmation_text(certification.block)
+            'confirmation_text': self.confirmation_text(certification.written_on)
         }
         self.nx_graph.add_edge(certifier.pubkey, identity.pubkey, attr_dict=arc)
 
@@ -153,7 +156,7 @@ class BaseGraph(QObject):
                 QLocale.dateFormat(QLocale(), QLocale.ShortFormat)
             ),
             'cert_time': certification.timestamp,
-            'confirmation_text': self.confirmation_text(certification.block)
+            'confirmation_text': self.confirmation_text(certification.written_on)
         }
 
         self.nx_graph.add_edge(identity.pubkey, certified.pubkey, attr_dict=arc)
diff --git a/src/sakia/root_servers.yml b/src/sakia/root_servers.yml
index 6fbb60434d6bef3069863ca0bbb4df596de5bf20..39b0defea76569f450dc6116f96a2565f368da72 100644
--- a/src/sakia/root_servers.yml
+++ b/src/sakia/root_servers.yml
@@ -4,3 +4,5 @@ fakenet:
 gtest:
     C4orqutdb3Nveur3xN5L2TduT1j8d2EZkJsWLmWuD2Sv:
     - "BASIC_MERKLED_API gtest.duniter.org 10900"
+    - "BASIC_MERKLED_API cgeek.fr 10900"
+    - "BASIC_MERKLED_API gtest.duniter.fr 10900"