diff --git a/app/services/email_importer.rb b/app/services/email_importer.rb
index e32c632..12364c1 100644
--- a/app/services/email_importer.rb
+++ b/app/services/email_importer.rb
@@ -47,7 +47,13 @@ class EmailImporter
         mail.parts[0].decoded
       end
     elsif mail.content_type && mail.content_type.match?(/\btext\/html\b/)
-      html_to_text_class.new.convert(mail.decoded)
+      plain_text = html_to_text_class.new.convert(mail.decoded)
+      if mail.content_type.match?(/\butf-8\b/)
+        # force utf-8 charset, even if we have to remve invalid characters
+        plain_text.encode!('UTF-8', 'binary', invalid: :replace, undef: :replace, replace: '')
+      else
+        plain_text
+      end
     else
       mail.decoded
     end