Sorry to jump in on your thread, but I just want to report that I'm also running Windows 10 and also have had the exact same issue as you for the past few days. Sometimes restarting the PC, or just the launcher, will fix it. However, more often than not, no matter how much I click the login button, nothing happens. I know it's not my firewall software (FFXIV and all related software has permission to send and receive data), and I know it's not my actual login details or one time password either. Would love to get some kind of workaround solution for this as my sub just renewed the other day, but I can't access the game most of the time!