diff --git a/be/database/migrations/2023_06_06_082226_add_deadline_to_subtasks_table.php b/be/database/migrations/2023_06_06_082226_add_deadline_to_subtasks_table.php
index 0c8b8b5..9a6a5a0 100644
--- a/be/database/migrations/2023_06_06_082226_add_deadline_to_subtasks_table.php
+++ b/be/database/migrations/2023_06_06_082226_add_deadline_to_subtasks_table.php
@@ -14,7 +14,7 @@ return new class extends Migration
     public function up()
     {
         Schema::table('sub_tasks', function (Blueprint $table) {
-            $table->timestamp('deadline')->after('tracked_time')->default(NULL);
+            $table->timestamp('deadline')->after('tracked_time')->nullable()->default(NULL);
         });
     }