Screenshot to convince you:  http://businessdirectoryplugin.com/wp-content/uploads/2016/09/plugins.png

What else can I provide you here to help figure this out?  Like I said, I have no error logs…it’s just not registering on the server.

EDIT (question):  What cookies does the plugin use or if it uses a session?  They need to know for caching purposes which one(s).

UPDATE:  I took this back to my hosting provider again and it works in the staging environment, but fails in production.  It’s something related to WPEngine’s caching, which is not inside of my control.  They are investigating now.  Anyone reading this thread who is a WPE customer should contact their support if they have trouble with the 5.7.x SP release. 

No sessions… and any login/user cookies are wp specific…

interesting… would be very interested in what they find… especially since the 5.7.1 release was very minor with only a handful of changes…

thanks for the info…

OK, finally found the issue.  Our host does “login protection” where they send custom parameters to wp-login.php.  See below:

In order to resolve the issue, we needed to disable our login protection. Basically, what our login protection does is it checks for a specific query argument that our WP Engine plugin appends to the end of a standard login request.

For example, if you go to http://site.com/wp-login.php and log in while monitoring the requests going through, you’ll see a POST request to http://site.com/wp-login.php?wpe-login=<instance-name>

In order to get your custom login form working properly with login protection enabled (which I would strongly recommend) you’ll need to modify the code of the login form to include that POST request.

Is there some way you can consider adding this support in a future release?  I’d hate to make my WP install less secure…and customizing your code makes the forum un-upgradeable.

if you know the needed query args to add to the url, you can already do it…  or if you need to POST it,you can filter the html output for the form and add it yourself…

you will want to use a standard wp filter on ‘sph_LoginForm’… so something like this:

add_filter('sph_LoginForm', 'my_login_form');
function my_login_form($out) {
    str_replace('</form>', '<input xxx></form>',$out);
    return $out;
}

note, I dont know what form element you want for posting, so just replace xxx with the rest of the form input element…