diff --git a/src/server/BreCal/database/sql_handler.py b/src/server/BreCal/database/sql_handler.py
index 80b8754..5440f20 100644
--- a/src/server/BreCal/database/sql_handler.py
+++ b/src/server/BreCal/database/sql_handler.py
@@ -33,7 +33,9 @@ def get_synchronous_shipcall_times_standalone(query_time:pd.Timestamp, all_df_ti
 
     returns: counts
     """
-    assert isinstance(query_time,pd.Timestamp)
+    assert (isinstance(query_time,pd.Timestamp)) or (pd.isnull(query_time)), f"expected a timestamp. Found type: {type(query_time)} with value: {query_time}"
+    if pd.isnull(query_time):
+        return 0
 
     # get a timedelta for each valid (not Null) time entry
     time_deltas_eta = [(query_time.to_pydatetime()-time_.to_pydatetime()) for time_ in all_df_times.loc[:,"eta_berth"] if not pd.isnull(time_)]
@@ -442,4 +444,6 @@ class SQLHandler():
 
     def count_synchronous_shipcall_times(self, query_time:pd.Timestamp, all_df_times:pd.DataFrame, delta_threshold=900)->int:
         """count all times entries, which are too close to the query_time. The {delta_threshold} determines the threshold. returns counts (int)"""
+        if all_df_times is None:
+            all_df_times = self.df_dict.get("times")
         return get_synchronous_shipcall_times_standalone(query_time, all_df_times, delta_threshold)
diff --git a/src/server/BreCal/validators/validation_rule_functions.py b/src/server/BreCal/validators/validation_rule_functions.py
index 24bbc62..ae3e3bc 100644
--- a/src/server/BreCal/validators/validation_rule_functions.py
+++ b/src/server/BreCal/validators/validation_rule_functions.py
@@ -920,6 +920,9 @@ class ValidationRuleFunctions(ValidationRuleBaseFunctions):
         Type: Global Rule
         Description: this validation rule checks, whether there are too many shipcalls with identical times to the query ETA.
         """
+        if all_times_agency is None:
+            all_times_agency = self.sql_handler.get_times_for_agency(non_null_column="eta_berth")
+
         # check, if the header is filled in (agency)
         if not self.check_if_header_exists(df_times, participant_type=ParticipantType.AGENCY): # if len(times_agency) != 1:
             return self.get_no_violation_default_output()
@@ -929,6 +932,7 @@ class ValidationRuleFunctions(ValidationRuleBaseFunctions):
         query_time = times_agency.iloc[0].eta_berth
 
         # count the number of times, where a times entry is very close to the query time (uses an internal threshold, such as 15 minutes)
+
         counts = self.sql_handler.count_synchronous_shipcall_times(query_time, all_df_times=all_times_agency)
         violation_state = counts > maximum_threshold
 
@@ -944,6 +948,9 @@ class ValidationRuleFunctions(ValidationRuleBaseFunctions):
         Type: Global Rule
         Description: this validation rule checks, whether there are too many shipcalls with identical times to the query ETD.
         """
+        if all_times_agency is None:
+            all_times_agency = self.sql_handler.get_times_for_agency(non_null_column="etd_berth")
+
         # check, if the header is filled in (agency)
         if not self.check_if_header_exists(df_times, participant_type=ParticipantType.AGENCY): #if len(times_agency) != 1:
             return self.get_no_violation_default_output()