diff --git a/seahub/api2/endpoints/admin/organizations.py b/seahub/api2/endpoints/admin/organizations.py
index 02a484b86f..384ec9336e 100644
--- a/seahub/api2/endpoints/admin/organizations.py
+++ b/seahub/api2/endpoints/admin/organizations.py
@@ -90,7 +90,7 @@ def gen_org_url_prefix(max_trial=None, length=20):
         Url prefix if succed, otherwise, ``None``.
     """
     def _gen_prefix():
-        url_prefix = 'org_' + get_random_string(
+        url_prefix = 'org-' + get_random_string(
             length, allowed_chars='abcdefghijklmnopqrstuvwxyz0123456789')
         if ccnet_api.get_org_by_url_prefix(url_prefix) is not None:
             logger.error("org url prefix, %s is duplicated" % url_prefix)
diff --git a/seahub/auth/views.py b/seahub/auth/views.py
index 844396e769..98c32bca0f 100644
--- a/seahub/auth/views.py
+++ b/seahub/auth/views.py
@@ -475,14 +475,21 @@ def multi_adfs_sso(request):
 
         try:
             org_saml_config = OrgSAMLConfig.objects.get_config_by_domain(domain)
+            if not org_saml_config:
+                render_data['error_msg'] = "Cannot find a SAML/ADFS config for the organization related to domain %s." % domain
+                return render(request, template_name, render_data)
             org_id = org_saml_config.org_id
             org = ccnet_api.get_org_by_id(org_id)
+            if not org:
+                render_data['error_msg'] = 'Cannot find an organization related to domain %s.' % domain
+                return render(request, template_name, render_data)
+            url_prefix = org.url_prefix
         except Exception as e:
             logger.error(e)
             render_data['error_msg'] = 'Error, please contact administrator.'
             return render(request, template_name, render_data)
 
-        return HttpResponseRedirect('/org/custom/%s/saml2/login/' % org.url_prefix)
+        return HttpResponseRedirect('/org/custom/%s/saml2/login/' % url_prefix)
 
     if request.method == "GET":
         return render(request, template_name, render_data)
diff --git a/seahub/organizations/views.py b/seahub/organizations/views.py
index ec67b93b55..95b50ff4c6 100644
--- a/seahub/organizations/views.py
+++ b/seahub/organizations/views.py
@@ -154,7 +154,7 @@ def gen_org_url_prefix(max_trial=None):
         Url prefix if succed, otherwise, ``None``.
     """
     def _gen_prefix():
-        url_prefix = 'org_' + get_random_string(
+        url_prefix = 'org-' + get_random_string(
             6, allowed_chars='abcdefghijklmnopqrstuvwxyz0123456789')
         if get_org_by_url_prefix(url_prefix) is not None:
             logger.info("org url prefix, %s is duplicated" % url_prefix)