diff --git a/openwisp_radius/migrations/0035_organizationradiussettings_sms_cooldown.py b/openwisp_radius/migrations/0035_organizationradiussettings_sms_cooldown.py
index 03b4b6bc..d0880276 100644
--- a/openwisp_radius/migrations/0035_organizationradiussettings_sms_cooldown.py
+++ b/openwisp_radius/migrations/0035_organizationradiussettings_sms_cooldown.py
@@ -4,6 +4,8 @@
 
 import openwisp_utils.fields
 
+from .. import settings as app_settings
+
 
 class Migration(migrations.Migration):
     dependencies = [
@@ -16,7 +18,7 @@ class Migration(migrations.Migration):
             name="sms_cooldown",
             field=openwisp_utils.fields.FallbackPositiveIntegerField(
                 blank=True,
-                fallback=30,
+                fallback=app_settings.SMS_COOLDOWN,
                 help_text=(
                     "Time period a user will have to wait before"
                     " requesting another SMS token (in seconds)."
diff --git a/openwisp_radius/migrations/0037_alter_organizationradiussettings_allowed_mobile_prefixes_and_more.py b/openwisp_radius/migrations/0037_alter_organizationradiussettings_allowed_mobile_prefixes_and_more.py
index cab2d8ea..e68cf6d9 100644
--- a/openwisp_radius/migrations/0037_alter_organizationradiussettings_allowed_mobile_prefixes_and_more.py
+++ b/openwisp_radius/migrations/0037_alter_organizationradiussettings_allowed_mobile_prefixes_and_more.py
@@ -1,4 +1,4 @@
-# Generated by Django 4.2.11 on 2024-07-17 11:02
+# Generated by Django 4.2.14 on 2024-08-07 16:38
 
 from django.db import migrations
 
@@ -58,19 +58,4 @@ class Migration(migrations.Migration):
                 verbose_name="Password reset URL",
             ),
         ),
-        migrations.AlterField(
-            model_name="organizationradiussettings",
-            name="sms_cooldown",
-            field=openwisp_utils.fields.FallbackPositiveIntegerField(
-                blank=True,
-                default=None,
-                fallback=app_settings.SMS_COOLDOWN,
-                help_text=(
-                    "Time period a user will have to wait before requesting"
-                    " another SMS token (in seconds)."
-                ),
-                null=True,
-                verbose_name="SMS Cooldown",
-            ),
-        ),
     ]
diff --git a/openwisp_radius/tests/test_admin.py b/openwisp_radius/tests/test_admin.py
index 461e158c..c76a55f0 100644
--- a/openwisp_radius/tests/test_admin.py
+++ b/openwisp_radius/tests/test_admin.py
@@ -674,7 +674,7 @@ def test_backward_compatible_default_password_reset_url(self):
             # The default value is set on project startup, hence
             # it also requires mocking.
             OrganizationRadiusSettings._meta.get_field('password_reset_url'),
-            'default',
+            'fallback',
             app_settings.DEFAULT_PASSWORD_RESET_URL,
         ):
             response = self.client.get(url)