I have been using this plugin for many years, but the upgrade to WP 4.6 seems to have broken it. First of all, all my settings were wiped out. After re-entering everything in the settings menu, I still cannot get it to work. I keep getting the SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting message when sending a test. I have doublechecked all my settings with my e-mail host, and everything is OK. Will look into using another SMTP plugin.
I am having the same problem (and am also on 3.5.2 and WP 3.6.1). There is no feedback to the person completing the form, the little arrows just keep spinning. We are also using the Easy WP SMTP plugin ver 1.0.4. When I deactivate that plugin, this problem goes away. However, we need to use SMTP.
