I have two similar (same theme) websites with TML. With both sites, I’ve updated to WP 4.3.1 and TML 6.4. On one site, everything is working great. On the site that uses SSL and W3 Total Cache, everything works except when resetting a password, it says key is invalid. W3 Total Cache is only caching static files and serving them from a CDN, so it’s not caching pages. Regardless, I deactivated it, but that didn’t solve the problem. I notice that when I click the lost password link, there’s a redirect that strips the query string and saves a cookie. The correct key and username/email is stored in the cookie. But the hidden fields “key” and “login” on the reset-password page are left blank. Since the only difference between the 2 sites is SSL, my guess is there is a problem reading the cookie when using https?