I'm having the same issue. I enter my correct .myshopify url, get the login screen and login.
After that I am redirected to https://apps.shopify.com/#login
When I click on the Login button, I get the error screen:
I have tried in Incognito mode and get the same problem.
Thanks for letting me know that you're also experiencing this issue.
What device are you using when this error pops up? Have you tried using another computer, or a mobile device to test this out instead?
Please keep me posted on the above!
I am unable to login. I keep getting the message unable to authenticate. Trying to work on a clients store. I’ve tried all your suggestions
Thanks for reaching out.
If you're using a staff account, it's important to make sure you have the correct permissions needed to download apps. Check out this help document for more details on this.
Can you also please provide me with a screenshot of the exact error message you're seeing? This will help me determine where this error is coming from.
I'm happy to help further once I have the above details!