diff --git a/app/signup/models.py b/app/signup/models.py
index 656053f..2b671fa 100644
--- a/app/signup/models.py
+++ b/app/signup/models.py
@@ -5,7 +5,7 @@ class Signup(models.Model):
     email = models.EmailField()
     created_at = models.DateTimeField(auto_now_add=True)
     anonymized_ip = models.GenericIPAddressField()
-    user_agent = models.CharField(max_length=255)
+    user_agent = models.CharField(max_length=255, blank=True)
     geoip = models.JSONField(null=True, blank=True)
     referrer = models.CharField(max_length=255, blank=True)
 
diff --git a/app/signup/tests.py b/app/signup/tests.py
index d32cb2a..ae85047 100644
--- a/app/signup/tests.py
+++ b/app/signup/tests.py
@@ -13,7 +13,7 @@ class SignupViewTest(TestCase):
         self.assertEqual(resp.status_code, 200)
         self.assertContains(resp, "Hosted Syncthing")
 
-    def test_ok_signup(self):
+    def test_signup_ok(self):
         resp = self.client.post(reverse("index"), {"email": "foo@example.com"},
                                 follow=True,
                                 HTTP_USER_AGENT="foo-agent",
@@ -26,3 +26,8 @@ class SignupViewTest(TestCase):
         self.assertEqual(obj.anonymized_ip, "127.0.0.0")
         self.assertEqual(obj.user_agent, "foo-agent")
         self.assertEqual(obj.referrer, "example.org/good-place")
+
+    def test_signup_badmail(self):
+        resp = self.client.post(reverse("index"), {"email": "x@x.x"})
+        self.assertEqual(resp.status_code, 200)
+        self.assertContains(resp, "Enter a valid email address.")
diff --git a/app/signup/views.py b/app/signup/views.py
index d9687e0..c71816c 100644
--- a/app/signup/views.py
+++ b/app/signup/views.py
@@ -33,7 +33,7 @@ def index(request):
         s = Signup(
             email=request.POST.get("email"),
             anonymized_ip=anonymous_ip,
-            user_agent=request.META['HTTP_USER_AGENT'],
+            user_agent=request.META.get('HTTP_USER_AGENT', ''),
             geoip=geoip,
             referrer=request.META.get('HTTP_REFERRER', ''),
         )
@@ -41,9 +41,8 @@ def index(request):
         try:
             s.clean_fields()
         except ValidationError as e:
-            print(e)
             return render(request, "signup/index.html",
-                          {"error_message": e.message})
+                          {"error_message": ", ".join(e.messages)})
 
         logging.info("registering email={}".format(request.POST.get("email")))
         try: