This is Lana from Shopify Support.
You mentioned that you were able to login, but it is still not working - do you mean that the customers cannot access your storefront? Or is your issue with the checkout?
The first thing you should look into here is your Plan - would you be able to go into Settings > Plans and make sure that you have selected a monthly paid plan that is not the Pause and Build plan? That is because on that plan you are able to access your admin and work on your store, but customers will not be able to checkout.
If you do have the correct plan selected, the issue might be that you still have a password page in place which is preventing customers from accessing the site. To remove the password page, you will need to go to Online store > Preferences, scroll down to the Password protection section:
After that you can check your storefront again, and it should open up straight away without any password page!
If you have already followed the steps I outlined above and you're still having issues, could you tell me a little bit more about what you're seeing? Any screenshots/further context would be very helpful if you can provide it!
Let me know if you have any questions.