diff --git a/app/email_utils.py b/app/email_utils.py
index ba2b7acc..9d6926b2 100644
--- a/app/email_utils.py
+++ b/app/email_utils.py
@@ -193,7 +193,7 @@ def send_cannot_create_domain_alias(user, alias, domain):
 def send_email(to_email, subject, plaintext, html=None):
     if NOT_SEND_EMAIL:
         LOG.d(
-            "send email with subject %s to %s, plaintext: %s",
+            "send email with subject '%s' to '%s', plaintext: %s",
             subject,
             to_email,
             plaintext,
diff --git a/cron.py b/cron.py
index 5765a330..3ed12027 100644
--- a/cron.py
+++ b/cron.py
@@ -12,7 +12,10 @@ from app.config import (
     ADMIN_EMAIL,
     MACAPP_APPLE_API_SECRET,
     APPLE_API_SECRET,
+    EMAIL_SERVERS_WITH_PRIORITY,
+    URL,
 )
+from app.dns_utils import get_mx_domains
 from app.email_utils import (
     send_email,
     send_trial_end_soon_email,
@@ -314,6 +317,41 @@ def sanity_check():
     LOG.d("Finish sanity check")
 
 
+def check_custom_domain():
+    LOG.d("Check verified domain for DNS issues")
+
+    for custom_domain in CustomDomain.query.filter(CustomDomain.verified == True):
+        mx_domains = get_mx_domains(custom_domain.domain)
+
+        if sorted(mx_domains) != sorted(EMAIL_SERVERS_WITH_PRIORITY):
+            user = custom_domain.user
+            LOG.exception(
+                "The MX record is not correctly set for %s %s %s",
+                custom_domain,
+                user,
+                mx_domains,
+            )
+
+            domain_dns_url = f"{URL}/dashboard/domains/{custom_domain.id}/dns"
+
+            send_email(
+                user.email,
+                f"Please update {custom_domain.domain} DNS on SimpleLogin",
+                render(
+                    "transactional/custom-domain-dns-issue.txt",
+                    custom_domain=custom_domain,
+                    name=user.name or "",
+                    domain_dns_url=domain_dns_url,
+                ),
+                render(
+                    "transactional/custom-domain-dns-issue.html",
+                    custom_domain=custom_domain,
+                    name=user.name or "",
+                    domain_dns_url=domain_dns_url,
+                ),
+            )
+
+
 def delete_old_monitoring():
     """
     Delete old monitoring records
@@ -341,6 +379,7 @@ if __name__ == "__main__":
             "poll_apple_subscription",
             "sanity_check",
             "delete_old_monitoring",
+            "check_custom_domain",
         ],
     )
     args = parser.parse_args()
@@ -372,3 +411,6 @@ if __name__ == "__main__":
         elif args.job == "delete_old_monitoring":
             LOG.d("Delete old monitoring records")
             delete_old_monitoring()
+        elif args.job == "check_custom_domain":
+            LOG.d("Check custom domain")
+            check_custom_domain()
diff --git a/crontab.yml b/crontab.yml
index f2461814..b5f6eb54 100644
--- a/crontab.yml
+++ b/crontab.yml
@@ -47,3 +47,8 @@ jobs:
     schedule: "0 14 * * *"
     captureStderr: true
 
+  - name: SimpleLogin Custom Domain check
+    command: python /code/cron.py -j check_custom_domain
+    shell: /bin/bash
+    schedule: "0 15 * * *"
+    captureStderr: true
diff --git a/templates/emails/transactional/custom-domain-dns-issue.html b/templates/emails/transactional/custom-domain-dns-issue.html
new file mode 100644
index 00000000..dea74d34
--- /dev/null
+++ b/templates/emails/transactional/custom-domain-dns-issue.html
@@ -0,0 +1,23 @@
+{% extends "base.html" %}
+
+{% block content %}
+  {{ render_text("Hi " + name) }}
+
+  {% call text() %}
+    We have detected that your domain <b>{{ custom_domain.domain }}</b> does not have the DNS set up correctly.
+  {% endcall %}
+
+  {% call text() %}
+    Please make sure to set up your domain following the instructions on your domain DNS page at
+    <a href="{{ domain_dns_url }}">{{ custom_domain.domain }} DNS</a>.
+  {% endcall %}
+
+  {% call text() %}
+    Feel free reply to this email if you have any question. <br>
+    Best, <br>
+    SimpleLogin team.
+  {% endcall %}
+
+{% endblock %}
+
+
diff --git a/templates/emails/transactional/custom-domain-dns-issue.txt b/templates/emails/transactional/custom-domain-dns-issue.txt
new file mode 100644
index 00000000..6379a302
--- /dev/null
+++ b/templates/emails/transactional/custom-domain-dns-issue.txt
@@ -0,0 +1,11 @@
+Hi {{name}}
+
+We have detected that your domain {{ custom_domain.domain }} does not have the DNS set up correctly.
+
+Please make sure to set up your domain following the instructions on your domain DNS page at:
+{{ domain_dns_url }}
+
+Feel free reply to this email if you have any question.
+
+Best,
+SimpleLogin team.
\ No newline at end of file