post.php “Page Not Found” Error

The plugin is not working with WordPress 5.0.3 and PHP 7.2. Whenever I try to create a new team and click “Publish”, I get a “wp-admin/post.php” “Page not found” error. I am using the Pro version of Team Builder, which hasn’t been updated in some time. I opened a ticket on the pro support forum as was told to “not use special characters”. This has nothing to do with that, as I am just trying to create a brand new team from scratch and can’t even save/publish it. Please help!