The error you're seeing would indicate that the account you're trying to access does not have the appropriate permissions for the store. The error can happen if the store owner has revoked your permissions, or if you're signing into the wrong account.
Are you the account owner? If you are the owner, then I suspect you're using the wrong email for the account. If you're certain that you are using the correct email and you're unable to access the admin, then you'll need to contact Shopify Support for further assistance.
As this is your first post in the Shopify Community I would recommend reading our guide on getting support from the Shopify Community here so you are best equipped when looking for support through these forum boards. We also have this great Introduction to Shopify section of our Help Center and a YouTube Channel which is jam-packed with how-to guides to help you get set up faster!
Let me know how you get on!
Moira | Social Care @ Shopify - Was my reply helpful? Click Like to let me know! - Was your question answered? Mark it as an Accepted Solution - To learn more visit the Shopify Help Center or the Shopify Blog