Hi @Samuel CHEN ,
Thanks for reaching out.
LAN1 Error
The AADSTS900561 error typically occurs when 3rd party cookies are being blocked by certain browsers.
You need to allow the URL (Azure portal) which you are trying to open to access as shown below in edge.
LAN2 Error
Whenever you sign in Azure portal using Microsoft Personal Account you by default get connected to the Microsoft Services tenant.
In this default tenant, you do not have any directory associated with it which you can confirm by navigating to settings.
As this is a standard tenant without any directory associated, you cannot perform actions such as creating new users, groups, enterprise applications, and so on. To perform administrative actions, you must have administrative access to the tenant.
Solution: For this purpose, you need to create your own tenant rather than using the Microsoft Services tenant.
To create a new tenant, open in-private/incognito browser window (just to avoid SSO), access https://azure.microsoft.com/en-us/free/ to create a free Azure account.
Reference - https://learn.microsoft.com/en-us/answers/questions/1377925/issue-while-logging-in-to-azure-entra-portal-aadst
Hope this will help.
Thanks,
Shweta
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