[Plugin: Contact Form 7] Spinning JS wheel keeps spinning

I am having the exact same issue. I have followed the suggest troubleshooting in the FAQ to no avail. This is issue is spread across 5 different sites (and 2 WP versions). I have tried disabling (on all 5 sites) all extensions except for Contact Form 7 as well as set to default theme…same issue. These sites are all hosted on one server (the contact forms worked before migrating to this server) so I’m fairly positive the issue is concentric to this server. However, I have test PHPsendmail and works fine and WordPress is able to send out from the server for new registration, comments, etc.
What are Contact Form 7’s requirements for the server?

Thanks in advance for any help.

I host it myself so have full control of the server. Anything else using phpsendmail works just fine so I’m curious if there is some special php module that needs loaded or something of that sort.

Yes and it is functioning. Have tested with the following script:

<?php
$to = “me@example.com”;
$subject = “Test PHP Sendmail”;
$message = “Hello! This is a simple email message.”;
$from = “test@example.com”;
$headers = “From:” . $from;
mail($to,$subject,$message,$headers);
echo “Mail Sent.”;
?>

The email delivers.

Mine, unfortunately, isn’t sending out (Just the Contact Form mail… everything else sends)

Yes I have. I am the admin of the mail server as well and have verified that when using Contact Form it doesn’t even try to talk to the SMTP server, but everything else goes through fine.