diff --git a/plinth/modules/backups/forms.py b/plinth/modules/backups/forms.py
index 0ee35be3c..23697bf14 100644
--- a/plinth/modules/backups/forms.py
+++ b/plinth/modules/backups/forms.py
@@ -233,8 +233,8 @@ class VerifySshHostkeyForm(forms.Form):
         """Initialize the form with selectable apps."""
         hostname = kwargs.pop('hostname')
         super().__init__(*args, **kwargs)
-        self.fields['ssh_public_key'].choices = self._get_all_public_keys(
-            hostname)
+        (self.fields['ssh_public_key'].choices,
+         self.keyscan_error) = self._get_all_public_keys(hostname)
 
     @staticmethod
     def _get_all_public_keys(hostname):
@@ -242,11 +242,12 @@ class VerifySshHostkeyForm(forms.Form):
         # Fetch public keys of ssh remote
         keyscan = subprocess.run(['ssh-keyscan', hostname],
                                  stdout=subprocess.PIPE,
-                                 stderr=subprocess.DEVNULL)
+                                 stderr=subprocess.PIPE)
         keys = keyscan.stdout.decode().splitlines()
+        error_message = keyscan.stderr.decode() if keyscan.returncode else None
         # Generate user-friendly fingerprints of public keys
         keygen = subprocess.run(['ssh-keygen', '-l', '-f', '-'],
                                 input=keyscan.stdout, stdout=subprocess.PIPE)
         fingerprints = keygen.stdout.decode().splitlines()
 
-        return zip(keys, fingerprints)
+        return zip(keys, fingerprints), error_message
diff --git a/plinth/modules/backups/templates/verify_ssh_hostkey.html b/plinth/modules/backups/templates/verify_ssh_hostkey.html
index 5c549abb6..9625a5b5b 100644
--- a/plinth/modules/backups/templates/verify_ssh_hostkey.html
+++ b/plinth/modules/backups/templates/verify_ssh_hostkey.html
@@ -35,6 +35,9 @@
           is up and accepting connections.
         {% endblocktrans %}
       </p>
+      {% if form.keyscan_error %}
+        <pre class="alert alert-danger">{{ form.keyscan_error }}</pre>
+      {% endif %}
     {% else %}
       <p>
         The authenticity of SSH host {{ hostname }} could not be established. The host advertises the following SSH public keys. Please verify any one of them.