diff --git a/lib/service/date_time/date_time.ex b/lib/service/date_time/date_time.ex
index d1aec54f2..9c2a82789 100644
--- a/lib/service/date_time/date_time.ex
+++ b/lib/service/date_time/date_time.ex
@@ -182,7 +182,7 @@ defmodule Mobilizon.Service.DateTime do
     compare_to_day = Keyword.get(options, :compare_to_day, Date.utc_today())
     compare_to = Keyword.get(options, :compare_to_datetime, DateTime.utc_now())
     start_time = Keyword.get(options, :start_time, @start_time)
-    timezone = Keyword.get(options, :timezone, "Etc/UTC")
+    timezone = Keyword.get(options, :timezone, "Etc/UTC") || "Etc/UTC"
     end_time = Keyword.get(options, :end_time, @end_time)
 
     DateTime.compare(compare_to, DateTime.new!(compare_to_day, start_time, timezone)) in [
diff --git a/lib/service/workers/notification.ex b/lib/service/workers/notification.ex
index 46d3310ed..3282169d2 100644
--- a/lib/service/workers/notification.ex
+++ b/lib/service/workers/notification.ex
@@ -46,7 +46,7 @@ defmodule Mobilizon.Service.Workers.Notification do
       }) do
     with %User{locale: locale, settings: %Setting{timezone: timezone, notification_on_day: true}} =
            user <- Users.get_user_with_settings!(user_id),
-         {start, tomorrow} <- calculate_start_end(1, timezone),
+         {start, tomorrow} <- calculate_start_end(1, timezone || "Etc/UTC"),
          %Page{
            elements: participations,
            total: total
@@ -80,7 +80,7 @@ defmodule Mobilizon.Service.Workers.Notification do
            locale: locale,
            settings: %Setting{timezone: timezone, notification_each_week: true}
          } = user <- Users.get_user_with_settings!(user_id),
-         {start, end_week} <- calculate_start_end(7, timezone),
+         {start, end_week} <- calculate_start_end(7, timezone || "Etc/UTC"),
          %Page{
            elements: participations,
            total: total