If you’re having trouble connecting Setary to your site and you see this error, it’s an error that’s being returned to us from your site.
One of the common issues is if you are using Advanced Custom Fields you may need to enable this plugin within Setary on your website. You can follow how to do this here.
Failing that, there could be another plugin that is conflicting with Setary. Try disabling plugins until it starts working. You can also find the specific error by checking the WordPress error logs on your server.