Hi Filip Magiera,
Thank you for reaching out to Microsoft Q&A Forum.
If your Azure subscription within the Microsoft Learn Sandbox directory was operational yesterday but is now inactive, there are several potential reasons for this change:
1.Azure subscriptions in the Microsoft Learn Sandbox directory often have limited durations and may expire after a certain period. Check to see if your subscription has reached its expiration date.
2.Some sandbox subscriptions have usage restrictions, and if you've surpassed these limits, your subscription may become invalid.
3.It's possible that technical issues within the sandbox environment or with your subscription itself have led to its deactivation. To resolve this issue:
Review Subscription Status: Confirm whether your subscription has expired or if you've exceeded any usage limits.
If your subscription has expired, you may need to renew it. Alternatively, if renewal isn't an option, request a new subscription.
Change Directory Tenants with your Azure Subscriptions: Change directory tenants with your individual VSS Azure subscriptions | Microsoft Learn
Thank you.