What must I do so that I can log in?
I'm Alex, with the Shopify team!
So sorry to hear that you've had an issue! It looks like you posted this about 24 hours ago - we were experiencing an issue with logging in to the admin at that time, but our engineers have deployed a fix - you should now not be seeing any barriers.
If you're still seeing any issues, however, please do let us know. You can reach back out to me here, or you can always give us a call or start a live chat at any time. We're open 24/7 for your convenience and always happy to assist!
Alex | Shopify