diff --git a/lib/algora/activities/activities.ex b/lib/algora/activities/activities.ex
index 69ee56c6a..36423d76e 100644
--- a/lib/algora/activities/activities.ex
+++ b/lib/algora/activities/activities.ex
@@ -59,13 +59,13 @@ defmodule Algora.Activities do
   @tables Map.keys(@schema_from_table)
   @user_attributes Map.keys(@table_from_user_relation)
 
-  def schema_from_table(name) when is_binary(name), do: name |> String.to_atom() |> schema_from_table()
+  def schema_from_table(name) when is_binary(name), do: name |> String.to_existing_atom() |> schema_from_table()
 
   def schema_from_table(name) when is_atom(name) do
     Map.fetch!(@schema_from_table, name)
   end
 
-  def table_from_schema(name) when is_binary(name), do: name |> String.to_atom() |> table_from_schema()
+  def table_from_schema(name) when is_binary(name), do: name |> String.to_existing_atom() |> table_from_schema()
 
   def table_from_schema(name) when is_atom(name) do
     Map.fetch!(@table_from_schema, name)