Good afternoon and thank you for posting on the Final Fantasy XIV Technical Support Forums.

When did this start happening? Do you recall anything updating/changing on your iMac that coincides with this?

If you are getting an HTTPS error, then this is likely a connection-related error. There are a few things you may want to check if you haven't tried them already:

Ensure that the latest version of Safari is installed on your Mac (even if you don't use Safari). Once Safari is up-to-date, please open the Safari browser and make sure that all Browser History and Cookies/Web Data have been DELETED. Please also make sure that "Cookies" are ACCEPTED and not being filtered. Once these options have been adjusted, please run the Apple Update program to check that all firmware is up-to-date on your Mac OS. Once this process is complete, please re-launch the FINAL FANTASY XIV game.

Please make sure all background applications (including anti-virus programs such as Norton, Kaspersky, etc.) have been disabled and/or closed to minimize game interference.

If you are using a wireless connection, try connecting your Mac to the router using an Ethernet cable.

Please note that as of this writing, the game is undergoing maintenance. As such, you won't be able to log in even if you are able to circumvent this problem. Maintenance will end 4/23 at 3AM PST.

We hope we can be of assistance in helping you enjoy the exciting world of Final Fantasy XIV!