1. How to Fix "Cookies Required" Issue in Safari on iPhone and Mac.
iPhone
To fix this, go to your iPhone's settings app, then go to 'Safari'. Make sure cookies are not disabled, and make sure 'prevent cross site tracking' IS disabled. Once this is done, your Safari cookie troubles should be no more.
Mac
Go to the Safari dropdown menu and select preferences. Once there, click 'Privacy' in the top panel. Make sure 'Block all cookies' is unchecked. Make sure 'Prevent cross-site tracking' IS unchecked. Once this is done, your Safari cookie troubles should be no more.
