Microsoft App Store Login Screen Blank White

Hello Annie, 

Thank you for your reply.

Let us try to create a new user account with different Microsoft account and check if the issue persist.

If you have already logged in with a Microsoft account, I suggest you to covert that Microsoft account into local account. Later login using newly created local account to create a different Microsoft account.

Step 1: To convert the account, you can do the following: 

1. Sign in to your Microsoft account on Windows 10.
2. Click Start and then PC settings.
3. Click Users and accounts and under Your Profile click Disconnect on the right of the screen.
4. Enter your Microsoft account's password, and click on Next.
5. Type in a Username, Password, and Password Hint that you want set for your Local account and click Next. Click on Sign out and Finish button. 

Step 2: Create new Microsoft account

Refer: Sign in with a Microsoft account 

Kindly let us know if you need any further assistance with the issue. We are glad to assist you.