diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index eb4e547fd..32b7e5221 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -108,8 +108,6 @@ rector_tests:
 #             - tests/app/vendor/
 
 unit_tests:
-    # temporarily allow failure due to problem with timezone
-    allow_failure: true
     stage: Tests
     image: gitea.champs-libres.be/chill-project/chill-skeleton-basic/base-image:php82
     script:
diff --git a/src/Bundle/ChillCalendarBundle/Tests/RemoteCalendar/Connector/MSGraph/CalendarSyncerTest.php b/src/Bundle/ChillCalendarBundle/Tests/RemoteCalendar/Connector/MSGraph/CalendarSyncerTest.php
index 8f6cb9335..e6196aead 100644
--- a/src/Bundle/ChillCalendarBundle/Tests/RemoteCalendar/Connector/MSGraph/CalendarSyncerTest.php
+++ b/src/Bundle/ChillCalendarBundle/Tests/RemoteCalendar/Connector/MSGraph/CalendarSyncerTest.php
@@ -356,20 +356,6 @@ final class CalendarSyncerTest extends TestCase
             }
         JSON;
 
-    protected function setUp(): void
-    {
-        parent::setUp();
-
-        // all tests should run when timezone = +02:00
-        $brussels = new \DateTimeZone('Europe/Brussels');
-
-        if (7200 === $brussels->getOffset(new \DateTimeImmutable())) {
-            date_default_timezone_set('Europe/Brussels');
-        } else {
-            date_default_timezone_set('Europe/Moscow');
-        }
-    }
-
     public function testHandleAttendeesConfirmingCalendar(): void
     {
         $machineHttpClient = new MockHttpClient([