Hi Bhuvan sai Jadhav,Thank you for reaching out to us on the Microsoft Q&A forum.
Please try signing out of your Learn profile and clear your browser's cache and history. Then, log back into your Learn profile using a new browser or incognito mode and activate your sandbox. Once the sandbox is activated, sign in to the Azure portal using the same Learn credentials.
After that, you can follow the instructions in the documentation to create the storage account. If you encounter any error messages, kindly share a screenshot of the error so we can assist you more effectively as mentioned by TP.
If the information is helpful, please accept the answer by clicking the "Upvote" and "Accept Answer" on the post. If you are still facing any issue, please let us know in the comments. We are glad to help you.