This happens all the time and when you refresh you get right back in, and it goes to the login page. Please do not worry about it and it does not mean you are blocked out or anything. May I suggest you completely log out of Shopify & close the window down & even restart your computer. Then after restart login again with your password etc & hopefully all OK. All the very best & good luck. I hope it works.
Nick here from Shopify.
Is this error still showing up for you? If so, can you let me know and send a screenshot of the exact error if possible to give some extra context on where exactly it is and what it looks like.
There are a few things you could try to see if it will work. Could you try it on a different internet IP, on the incognito tab and a different device to see if that helps in any way? You could also clear your browser cache if none of the previous suggestions do the trick.
Looking forward to hearing from you and hopefully one of the above sorts this out.
All the best, Nick