I am having the same issue. I have had to temporarily remove the ajax login and revert to using the standard wp-login.php form. It’s not a good user experience!
I have no issues on my test server but wonder if the ajax calls are returning correctly? I’m using inmotionhosting and my site is located in the /public_html rather than the root folder. Could this be the cause of the error?
Please help with the fix!?
Thanks