diff --git a/lib/import/otrs/article_customer.rb b/lib/import/otrs/article_customer.rb
index 22df4cafa..1ee83c56a 100644
--- a/lib/import/otrs/article_customer.rb
+++ b/lib/import/otrs/article_customer.rb
@@ -13,6 +13,7 @@ module Import
 
         def find(article)
           email = local_email(article['From'])
+          return if !email
           user   = ::User.find_by(email: email)
           user ||= ::User.find_by(login: email)
           user
@@ -20,7 +21,9 @@ module Import
 
         def local_email(from)
           # TODO: should get unified with User#check_email
-          extract_email(from).downcase
+          email = extract_email(from)
+          return if !email
+          email.downcase
         end
 
         private
diff --git a/spec/lib/import/otrs/article_customer_sepc.rb b/spec/lib/import/otrs/article_customer_sepc.rb
index 2bf091efc..0645271b0 100644
--- a/spec/lib/import/otrs/article_customer_sepc.rb
+++ b/spec/lib/import/otrs/article_customer_sepc.rb
@@ -47,4 +47,23 @@ RSpec.describe Import::OTRS::ArticleCustomer do
     expect(User.last.email).to eq('user@example.com')
     expect(User.last.login).to eq('user@example.com')
   end
+
+  context '.find' do
+
+    it 'returns nil if no email could be found' do
+      expect(described_class.find({})).to be nil
+    end
+  end
+
+  context '.local_email' do
+
+    it 'returns nil if no email could be found' do
+      expect(described_class.local_email(nil)).to be nil
+    end
+
+    it 'returns the parameter if no email could be found' do
+      not_an_email = 'thisisnotanemail'
+      expect(described_class.local_email(not_an_email)).to eq(not_an_email)
+    end
+  end
 end