diff --git a/src/server/BreCal/database/sql_handler.py b/src/server/BreCal/database/sql_handler.py
index f715b4b..f34f345 100644
--- a/src/server/BreCal/database/sql_handler.py
+++ b/src/server/BreCal/database/sql_handler.py
@@ -207,7 +207,8 @@ class SQLHandler():
         returns: participant_id_list, where every element is an int
         """
         df = self.df_dict.get("shipcall_participant_map")
-        df = df.set_index('shipcall_id', inplace=False)
+        if 'shipcall_id' in list(df.columns):
+            df = df.set_index('shipcall_id', inplace=False)
         
         # the 'if' call is needed to ensure, that no Exception is raised, when the shipcall_id is not present in the df
         participant_id_list = df.loc[shipcall_id, "participant_id"].tolist() if shipcall_id in list(df.index) else []