diff --git a/uffd/default_config.cfg b/uffd/default_config.cfg
index 6546b0024d95cc9f5665055e7f99e25da6bc95e1..71bb0f78a9ab6b77e6951d8b70c321ecde630aae 100644
--- a/uffd/default_config.cfg
+++ b/uffd/default_config.cfg
@@ -31,7 +31,7 @@ ACL_SIGNUP_GROUP="uffd_signup"
 
 MAIL_SERVER='' # e.g. example.com
 MAIL_PORT=465
-MAIL_USERNAME='yourId@example.com'
+MAIL_USERNAME='yourId@example.com' # set to empty string to disable authentication
 MAIL_PASSWORD='*****'
 MAIL_USE_STARTTLS=True
 MAIL_FROM_ADDRESS='foo@bar.com'
diff --git a/uffd/sendmail.py b/uffd/sendmail.py
index bf36ea8624253c35e9a7a7527b708de252b0b3ef..83b8960a29956fcf4927d39904a937bf0c5bd355 100644
--- a/uffd/sendmail.py
+++ b/uffd/sendmail.py
@@ -24,7 +24,8 @@ def sendmail(addr, subject, template_name, **kwargs):
 		server = smtplib.SMTP(host=current_app.config['MAIL_SERVER'], port=current_app.config['MAIL_PORT'])
 		if current_app.config['MAIL_USE_STARTTLS']:
 			server.starttls()
-		server.login(current_app.config['MAIL_USERNAME'], current_app.config['MAIL_PASSWORD'])
+		if current_app.config['MAIL_USERNAME']:
+			server.login(current_app.config['MAIL_USERNAME'], current_app.config['MAIL_PASSWORD'])
 		server.send_message(msg)
 		server.quit()
 		if current_app.debug: