This is an accepted solution.
Ash here from the Shopify team. Welcome to the Shopify Community!
I'm sorry to hear you're having some issues accessing the Shopify App Store. I'm happy to help out with this! Based on the error message you received, it sounds like this may be an issue that could be resolved using some troubleshooting steps. Could you please try the following steps and then try accessing the App Store again? Here are the steps:
Once you've completed the above steps and tried again to access the App Store, please reply back here and let me know the results! If you continue to experience any issues, please take a screenshot of the error and send it to me in a reply to this post.