Hi Philipp Kendzior,
We appreciate your engagement with us on the Microsoft Q&A forum.
Based on your query, it appears you are encountering difficulties accessing the cloud shell instance of the sandbox. As advised by Babafemi Bulugbe, please try accessing the sandbox using an Incognito tab or a different browser. Additionally, ensure that your internet connection is stable. Clearing your browser cache and cookies may help resolve issues with loading resources.
To further address this issue, please follow the troubleshooting steps outlined below:
- Refresh the page to resolve any temporary glitches and reactivate the sandbox. You may need to solve puzzles, review permissions, and accept any necessary prompts. Please be aware that you might need to wait a few minutes for your existing sandbox to expire, as they are valid for one hour.
- Attempt to log in with a new personal Microsoft email account using a completely different browser. If you do not have a personal Microsoft account, please create a new free Microsoft account. Note that a Microsoft account, such as Office 365 or Outlook.com, is required for sandbox access.
If you continue to experience issues, please let us know in the comments. We are here to assist you.
If you find this information helpful, please consider clicking the "Upvote" and "Accept Answer" buttons on the post.
Thank you.